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Puma 1998 (06.1997-12.2001)

Climate Control System - General Information - Climate Control System Puma 1998 (06/1997-12/2001)
Diagnosis and Testing

Inspection and Verification

  1. Verify the customer concern.
  1. Visually inspect for the following mechanical and electrical causes for the concern.

Visual Inspection Chart

Mechanical Electrical
  • Refrigerant lines
  • Drive belt
  • Coolant level
  • Blanking cap of coolant system reservoir
  • Coolant hoses
  • Circuit(s)
  • Connector(s)
  1. Repair any faults found during the visual inspection before proceeding to the next steps.
  1. If the concern is still present after this check refer to the Symptom Chart and proceed in accordance with the fault symptom.

Symptom Chart

Symptom Possible Sources Action
Malfunction of the heater
*
Fuse(s)
*
Heater control module
*
Heater control valve
*
Circuit(s)
*
GO to Pinpoint Test A.
Malfunction of the heater blower
*
Circuit(s)
*
Heater blower motor
*
Heater blower switch
*
Heater blower resistor
*
GO to Pinpoint Test B.
Air conditioning inoperative (heater blower motor OK)
*
Fuse(s)
*
Circuit(s)
*
A/C compressor clutch
*
A/C compressor clutch diode
*
A/C relay
*
A/C WOT relay
*
A/C compressor switch
*
Dual pressure switch
*
Heater control module
*
PCM/EEC.
*
Refrigerant circuit
*
Quantity of refrigerant
*
GO to Pinpoint Test C.
Inadequate performance from the air conditioning system
*
Condenser
*
Radiator fan control
*
A/C compressor switch
*
Dual pressure switch
*
Refrigerant circuit
*
Quantity of refrigerant
*
CHECK the refrigerant circuit. For more information please refer to the Component Checks at the end of this diagnosis section.
Malfunction of the air recirculation valve
*
Fuse(s)
*
Circuit(s)
*
Air recirculation valve control motor
*
Heater control module
*
GO to Pinpoint Test D.
Condensation water from the air conditioning system in the footwell
*
A/C outlet line
*
Check that the air conditioning outlet line is routed correctly.

Pinpoint Tests

PINPOINT TEST A : MALFUNCTION OF THE HEATER
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
A1: DETERMINE THE CONDITIONS UNDER WHICH THE FAULT OCCURS
1
Check the operation of the heater.

Is the heater permanently cold?
Yes
The heater is permanently cold: GO to A14.
No
The heater is permanently hot: GO to A2.
A2: CHECK THE HEATER CONTROL VALVE
WARNING:
WARNING:The heater control valve may be very hot.
NOTE:
NOTE:The heater control valve reacts with a delay to changes in the temperature selection.
1
Ignition switch in position II.
2
Start the engine.
3
Set the temperature control switch to the middle temperature.
4
With the engine running, check to see whether the heater control valve is pulsing.

Is the valve pulsing?
Yes
REMOVE the heater control valve, CHECK for blockages and RENEW as required. CHECK the operation of the system.
No
GO to A3.
A3: CHECK FUSE F13
1
Ignition switch in position 0.
2
CHECK Fuse F13 (CJB).
3
Check fuse F13 (15 A)

Is the fuse OK?
Yes
GO to A4.
No
RENEW fuse F13 (15 A). CHECK the operation of the system. If the fuse blows again immediately after installing, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
A4: CHECK THE VOLTAGE SUPPLY TO FUSE F13
1
Connect Fuse F13 (CJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F13 (15 A) and ground.

Is battery voltage displayed?
Yes
GO to A5.
No
REPAIR the voltage supply to fuse F13 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
A5: CHECK FUSE F2
1
Ignition switch in position 0.
2
CHECK Fuse F2 (CJB).
3
Check fuse F2 (10 A)

Is the fuse OK?
Yes
GO to A6.
No
RENEW fuse F2 (10 A). CHECK the operation of the system. If the fuse blows again immediately after installing, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
A6: CHECK THE VOLTAGE SUPPLY TO FUSE F2
1
Connect Fuse F2 (CJB).
2
Measure the voltage between fuse F2 (10 A) and ground.

Is battery voltage displayed?
Yes
GO to A7.
No
REPAIR the voltage supply to fuse F2 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
A7: CHECK THE VOLTAGE AT THE HEATER CONTROL VALVE
1
Ignition switch in position 0.
2
Disconnect Heater control valve (C42).
3
Ignition switch in position II.

4
Measure the voltage between the heater control valve, connector C42, pin 1, circuit 14-CA82 (VT/BK), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to A8.
No
LOCATE and RECTIFY open circuit in circuit 14-CA82 (VT/BK) between the heater control valve and fuse F13 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
A8: CHECK THE HEATER CONTROL VALVE
1
Ignition switch in position 0.

2
Measure the resistance between the heater control valve, connector C42, pin 1 and pin 2, component side.

Does the reading show a resistance between 10 and 25 Ohm?
Yes
GO to A9.
No
RENEW the heater control valve. CHECK the operation of the system.
A9: CHECK THE HEATER CONTROL VALVE
1
Ignition switch in position II.
2
Start the engine.
3
Set the temperature control switch to the middle temperature.

4
Measure the voltage between the heater control valve, connector C42, pin 1, circuit 14-CA82 (VT/BK) and pin 2, circuit 31S-CA82 (BK/GN), wiring harness side.

Does the measurement vary periodically between 0 Volt and battery voltage?
Yes
REMOVE the heater control valve, CHECK for blockages and RENEW as required. CHECK the operation of the system.
No
GO to A10.
A10: CHECK THE VOLTAGE SUPPLY TO THE HEATER CONTROL MODULE
1
Ignition switch in position 0.
2
Disconnect Heater control module C41.
3
Ignition switch in position II.

4
Measure the voltage between the heater control module, connector C41, pin 12, circuit 14-CA45A (VT), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to A11.
No
LOCATE and RECTIFY open circuit in circuit 14-CA45A (VT) between the heater control module and fuse F13 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
A11: CHECK THE VOLTAGE SUPPLY TO THE HEATER CONTROL MODULE
1
Ignition switch in position 0.

2
Measure the voltage between the heater control module, connector C41, pin 2, circuit 29-CA83 (OG/GN), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to A12.
No
LOCATE and RECTIFY open circuit in circuit 29-CA83 (OG/GN) between the heater control module and fuse F2 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
A12: CHECK THE GROUND CONNECTION OF THE HEATER CONTROL MODULE

1
Measure the resistance between the heater control module, connector C41, pin 6, circuit 91-CA83 (BK/RD), wiring harness side and ground.

Is less than 2 Ohm displayed?
Yes
GO to A13.
No
LOCATE and RECTIFY open circuit in circuit 91-CA83 (BK/RD) between the heater control module and ground connection G4 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
A13: CHECK THE CONTROL LINE BETWEEN THE HEATER CONTROL MODULE AND THE HEATER CONTROL VALVE

1
Measure the resistance between the heater control module, connector C41, pin 5, circuit 31S-CA82 (BK/GN), wiring harness side and the heater control valve, connector C42, pin 2, circuit 31S-CA82 (BK/GN), wiring harness side.

Is less than 2 Ohm displayed?
Yes
CHECK and if necessary RENEW the heater control module. CHECK the operation of the system.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA82 (BK/GN) between the heater control module and the heater control valve with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
A14: CHECK THE HEATER CONTROL VALVE
1
Ignition switch in position 0.
2
Disconnect Heater control valve (C42).
3
Ignition switch in position II.
4
Start the engine.
5
Set the temperature switch to the highest setting.
6
Check the operation of the heater.

Does the heater warm up?
Yes
GO to A15.
No
CHECK whether the coolant hoses are routed correctly. If the coolant circuit is OK, REMOVE the heater control valve, CHECK for blockages and if necessary RENEW. CHECK the operation of the system.
A15: CHECK THE HEATER CONTROL MODULE
1
Ignition switch in position 0.
2
Connect Heater control valve C42.
3
Disconnect Heater control module C41.
4
Ignition switch in position II.
5
Start the engine.
6
Set the temperature switch to the highest setting.
7
Check the operation of the heater.

Does the heater warm up?
Yes
GO to A16.
No
LOCATE and RECTIFY short circuit to ground in circuit 31-CA82 (BK/GN) between the heater control valve and the heater control module with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
A16: CHECK THE SIGNAL FROM THE REVOLUTION COUNTER
NOTE:
NOTE:If the heater control module does not receive a signal from the revolution counter then the heater will stay cold permanently.
1
Ignition switch in position II.
2
Start the engine.

3
Measure the voltage between the heater control module, connector C41, pin 1, circuit 8-GB10A (WH/BK), wiring harness side and ground.

Is a voltage of 7 Volt displayed?
Yes
CHECK and if necessary RENEW the heater control module. CHECK the operation of the system.
No
LOCATE and RECTIFY open circuit in circuit 8-GB10A (WH/BK) between the heater control module and the instrument cluster with the aid of the Wiring Diagrams Binder. If the circuit is OK, CHECK the instrument cluster. CHECK the operation of the system.

PINPOINT TEST B : MALFUNCTION OF THE HEATER BLOWER
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
B1: DETERMINE THE CONDITIONS UNDER WHICH THE FAULT OCCURS
1
Ignition switch in position II.
2
Test all of the speeds of the heater blower motor.

Is the heater blower motor completely inoperative?
Yes
GO to B2.
No
GO to B10.
B2: CHECK FUSE F16
1
Ignition switch in position 0.
2
CHECK Fuse F16 (CJB).
3
Check fuse F16 (30 A)

Is the fuse OK?
Yes
GO to B3.
No
RENEW fuse F16 (30 A). CHECK the operation of the system. If the fuse blows again immediately after installing, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
B3: CHECK THE VOLTAGE SUPPLY TO FUSE F16
1
Connect Fuse F16 (CJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F16 (30 A) and ground.

Is battery voltage displayed?
Yes
GO to B4.
No
REPAIR the voltage supply to fuse F16 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B4: CHECK THE VOLTAGE SUPPLY TO THE BLOWER MOTOR
1
Ignition switch in position 0.
2
Disconnect Heater blower motor C221.
3
Ignition switch in position II.

4
Measure the voltage between the blower motor, connector C221, pin 1, circuit 14-CA18 (VT/OG), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to B5.
No
LOCATE and RECTIFY open circuit in circuit 14-CA18 (VT/OG) between the heater blower motor and fuse F16 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B5: CHECK THE GROUND CONNECTION OF THE HEATER BLOWER MOTOR
1
Ignition switch in position 0.
2
Set the heater blower switch to the highest speed setting.

3
Measure the resistance between the heater blower motor C221, pin 2, circuit 31S-CA18 (BK/RD), wiring harness side and ground.

Is less than 2 Ohm displayed?
Yes
CHECK and if necessary RENEW the heater blower motor. CHECK the operation of the system
No
Vehicles built before 09/99: GO to B6.
Vehicles built from 09/99 GO to B8.
B6: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER MOTOR AND THE HEATER BLOWER SWITCH
1
Disconnect Heater blower switch C38.

2
Measure the resistance between the heater blower motor, connector C221, pin 2, circuit 31S-CA18 (BK/RD), wiring harness side and the heater blower switch, connector C38, pin 4, circuit 31S-CA33 (BK/OG), wiring harness side.

Is less than 2 Ohm displayed?
Yes
GO to B7.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA18 (BK/RD) between the heater blower motor and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B7: CHECK THE GROUND CONNECTION OF THE HEATER BLOWER SWITCH

1
Measure the resistance between the heater blower switch, connector C38, pin 6, circuit 31-CA25 (BK), wiring harness side and ground.

Is less than 2 Ohm displayed?
Yes
CHECK and if necessary RENEW the heater blower switch. CHECK the operation of the system
No
LOCATE and RECTIFY open circuit in circuit 31-CA25 (BK) between the heater blower switch and ground connection G6 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B8: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER MOTOR AND THE HEATER BLOWER SWITCH
1
Disconnect Heater blower switch C1038.

2
Measure the resistance between the heater blower motor, connector C221, pin 2, circuit 31S-CA18 (BK/RD), wiring harness side and the heater blower switch, connector C1038, pin 6, circuit 31S-CA33 (BK/OG), wiring harness side.

Is less than 2 Ohm displayed?
Yes
GO to B9.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA18 (BK/RD) between the heater blower motor and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B9: CHECK THE GROUND CONNECTION OF THE HEATER BLOWER SWITCH

1
Measure the resistance between the heater blower switch, connector C1038, pin 2, circuit 31-CA25 (BK), wiring harness side and ground.

Is less than 2 Ohm displayed?
Yes
CHECK and if necessary RENEW the heater blower switch. CHECK the operation of the system
No
LOCATE and RECTIFY open circuit in circuit 31-CA25 (BK) between the heater blower switch and ground connection G6 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B10: DETERMINE THE CONDITIONS UNDER WHICH THE FAULT OCCURS
1
Ignition switch in position II.
2
Set the heater blower switch to the highest speed setting.

Is the heater blower motor inoperative?
Yes
Vehicles built before 09/99: GO to B11.
Vehicles built from 09/99 GO to B12.
No
Vehicles built before 09/99: GO to B13.
Vehicles built from 09/99 GO to B18.
B11: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER MOTOR AND THE HEATER BLOWER SWITCH
1
Ignition switch in position 0.
2
Disconnect Heater blower switch C38.
3
Disconnect Heater blower motor C221.

4
Measure the resistance between the heater blower motor, connector C221, pin 2, circuit 31S-CA18 (BK/RD), wiring harness side and the heater blower switch, connector C38, pin 4, circuit 31S-CA33 (BK/OG), wiring harness side.

Is less than 2 Ohm displayed?
Yes
CHECK and if necessary RENEW the heater blower switch. CHECK the operation of the system
No
LOCATE and RECTIFY open circuit in circuit 31S-CA33 (BK/OG) between the heater blower motor and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B12: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER MOTOR AND THE HEATER BLOWER SWITCH
1
Ignition switch in position 0.
2
Disconnect Heater blower switch C1038.
3
Disconnect Heater blower motor C221.

4
Measure the resistance between the heater blower motor, connector C221, pin 2, circuit 31S-CA18 (BK/RD), wiring harness side and the heater blower switch, connector C1038, pin 6, circuit 31S-CA33 (BK/OG), wiring harness side.

Is less than 2 Ohm displayed?
Yes
CHECK and if necessary RENEW the heater blower switch. CHECK the operation of the system
No
LOCATE and RECTIFY open circuit in circuit 31S-CA33 (BK/OG) between the heater blower motor and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B13: CHECK THE HEATER BLOWER SWITCH
1
Ignition switch in position 0.
2
Disconnect Heater blower switch C38.
3
Ignition switch in position II.
4
Measure the voltage between the heater blower switch, connector C38, pin 1, circuit 31S-CA32 (BK/BU), wiring harness side and ground.
5
Measure the voltage between the heater blower switch, connector C38, pin 2, circuit 31S-CA31 (BK/YE), wiring harness side and ground.

6
Measure the voltage between the heater blower switch, connector C38, pin 3, circuit 31S-CA30 (BK/WH), wiring harness side and ground.

Is battery voltage displayed in all measurements?
Yes
CHECK and if necessary RENEW the heater blower switch. CHECK the operation of the system
No
GO to B14.
B14: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER MOTOR AND THE HEATER BLOWER RESISTOR
1
Ignition switch in position 0.
2
Disconnect Heater blower resistor C220.
3
Ignition switch in position II.

4
Measure the voltage between the heater blower resistor, connector C220, pin 1, circuit 31S-CA18A (BK/RD), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to B15.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA18A (BK/RD) between the heater blower motor and the heater blower resistor with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B15: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER RESISTOR AND THE HEATER BLOWER SWITCH
1
Ignition switch in position 0.

2
Measure the resistance between the heater blower resistor, connector C220, pin 4, circuit 31S-CA32 (BK/BU), wiring harness side and the heater blower switch, connector C38, pin 1, circuit 31S-CA32 (BK/BU), wiring harness side.

Is less than 2 Ohm displayed?
Yes
GO to B16.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA32 (BK/BU) between the heater blower resistor and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B16: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER RESISTOR AND THE HEATER BLOWER SWITCH

1
Measure the resistance between the heater blower resistor, connector C220, pin 2, circuit 31S-CA31 (BK/YE), wiring harness side and the heater blower switch, connector C38, pin 2, circuit 31S-CA31 (BK/YE), wiring harness side.

Is less than 2 Ohm displayed?
Yes
GO to B17.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA31 (BK/YE) between the heater blower resistor and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B17: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER RESISTOR AND THE HEATER BLOWER SWITCH

1
Measure the resistance between the heater blower resistor, connector C220, pin 3, circuit 31S-CA30 (BK/WH), wiring harness side and the heater blower switch, connector C38, pin 3, circuit 31S-CA30 (BK/WH), wiring harness side.

Is less than 2 Ohm displayed?
Yes
CHECK and if necessary RENEW the heater blower resistor. CHECK the operation of the system
No
LOCATE and RECTIFY open circuit in circuit 31S-CA30 (BK/YE) between the heater blower resistor and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B18: CHECK THE HEATER BLOWER SWITCH
1
Ignition switch in position 0.
2
Disconnect Heater blower switch C1038.
3
Ignition switch in position II.
4
Measure the voltage between the heater blower switch, connector C1038, pin 5, circuit 31S-CA32 (BK/BU), wiring harness side and ground.
5
Measure the voltage between the heater blower switch, connector C1038, pin 3, circuit 31S-CA31 (BK/YE), wiring harness side and ground.

6
Measure the voltage between the heater blower switch, connector C1038, pin 1, circuit 31S-CA30 (BK/WH), wiring harness side and ground.

Is battery voltage displayed in all measurements?
Yes
CHECK and if necessary RENEW the heater blower switch. CHECK the operation of the system
No
GO to B19.
B19: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER MOTOR AND THE HEATER BLOWER RESISTOR
1
Ignition switch in position 0.
2
Disconnect Heater blower resistor C220.
3
Ignition switch in position II.

4
Measure the voltage between the heater blower resistor, connector C220, pin 1, circuit 31S-CA18A (BK/RD), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to B20.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA18A (BK/RD) between the heater blower motor and the heater blower resistor with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B20: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER RESISTOR AND THE HEATER BLOWER SWITCH
1
Ignition switch in position 0.

2
Measure the resistance between the heater blower resistor, connector C220, pin 4, circuit 31S-CA32 (BK/BU), wiring harness side and the heater blower switch, connector C1038, pin 5, circuit 31S-CA32 (BK/BU), wiring harness side.

Is less than 2 Ohm displayed?
Yes
GO to B21.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA32 (BK/BU) between the heater blower resistor and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B21: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER RESISTOR AND THE HEATER BLOWER SWITCH

1
Measure the resistance between the heater blower resistor, connector C220, pin 3, circuit 31S-CA31 (BK/YE), wiring harness side and the heater blower switch, connector C1038, pin 2, circuit 31S-CA31 (BK/YE), wiring harness side.

Is less than 2 Ohm displayed?
Yes
GO to B22.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA31 (BK/YE) between the heater blower resistor and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
B22: CHECK THE CONNECTION BETWEEN THE HEATER BLOWER RESISTOR AND THE HEATER BLOWER SWITCH

1
Measure the resistance between the heater blower resistor, connector C220, pin 1, circuit 31S-CA30 (BK/WH), wiring harness side and the heater blower switch, connector C1038, pin 3, circuit 31S-CA30 (BK/WH), wiring harness side.

Is less than 2 Ohm displayed?
Yes
CHECK and if necessary RENEW the heater blower resistor. CHECK the operation of the system
No
LOCATE and RECTIFY open circuit in circuit 31S-CA30 (BK/YE) between the heater blower resistor and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.

PINPOINT TEST C : AIR CONDITIONING INOPERATIVE (HEATER BLOWER OK)
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
C1: CHECK FUSE F2
1
Ignition switch in position 0.
2
CHECK Fuse F2 (CJB).
3
Check fuse F2 (10 A)

Is the fuse OK?
Yes
GO to C2.
No
RENEW fuse F2 (10 A). CHECK the operation of the system. If the fuse blows again immediately after installing, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
C2: MEASURE THE VOLTAGE AT FUSE F2
1
Connect Fuse F2 (CJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F2 (10 A) and ground.

Is battery voltage displayed?
Yes
GO to C3.
No
REPAIR the voltage supply to fuse F2 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C3: CHECK FUSE F13
1
Ignition switch in position 0.
2
CHECK Fuse F13 (CJB).
3
Check fuse F13 (15 A)

Is the fuse OK?
Yes
GO to C4.
No
RENEW fuse F13 (15 A). CHECK the operation of the system. If the fuse blows again immediately after installing, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
C4: CHECK VOLTAGE AT FUSE F13
1
Connect Fuse F13 (CJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F13 (15 A) and ground.

Is battery voltage displayed?
Yes
Vehicles built before 02/00: GO to C5.
Vehicles built from 02/00 GO to C9.
No
REPAIR the voltage supply to fuse F13 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C5: CHECK FUSE F28
1
Ignition switch in position 0.
2
CHECK Fuse F28 (BJB).
3
Check fuse F28 (15 A)

Is the fuse OK?
Yes
GO to C6.
No
RENEW fuse F28 (15 A). CHECK the operation of the system. If the fuse blows again immediately after installing, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
C6: CHECK VOLTAGE AT FUSE F28
1
Connect Fuse F28 (BJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F28 (15 A) and ground.

Is battery voltage displayed?
Yes
GO to C7.
No
REPAIR the voltage supply to fuse F28 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C7: CHECK FUSE F29
1
Ignition switch in position 0.
2
CHECK Fuse F29 (BJB).
3
Check fuse F29 (20 A)

Is the fuse OK?
Yes
GO to C8.
No
RENEW fuse F29 (20 A). CHECK the operation of the system. If the fuse blows again immediately after installing, CHECK and if necessary RENEW the A/C compressor clutch diode. If the diode is OK, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
C8: CHECK VOLTAGE AT FUSE F29
1
Connect Fuse F29 (BJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F29 (20 A) and ground.

Is battery voltage displayed?
Yes
GO to C13.
No
REPAIR the voltage supply to fuse F29 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C9: CHECK FUSE F30
1
Ignition switch in position 0.
2
CHECK Fuse F28 (BJB).
3
Check fuse F30 (15 A)

Is the fuse OK?
Yes
GO to C10.
No
RENEW fuse F30 (15 A). CHECK the operation of the system. If the fuse blows again immediately after installing, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
C10: CHECK THE VOLTAGE AT FUSE F30
1
Connect Fuse F30 (BJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F30 (15 A) and ground.

Is battery voltage displayed?
Yes
GO to C11.
No
REPAIR the voltage supply to fuse F30 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C11: CHECK FUSE F31
1
Ignition switch in position 0.
2
CHECK Fuse F31 (BJB).
3
Check fuse F31 (20 A)

Is the fuse OK?
Yes
GO to C12.
No
RENEW fuse F31 (20 A). CHECK the operation of the system. If the fuse blows again immediately after installing, CHECK and if necessary RENEW the A/C compressor clutch diode. If the diode is OK, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
C12: CHECK VOLTAGE AT FUSE F31
1
Connect Fuse F31 (BJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F31 (20 A) and ground.

Is battery voltage displayed?
Yes
GO to C13.
No
REPAIR the voltage supply to fuse F31 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C13: CHECK THE VOLTAGE SUPPLY TO THE A/C WOT RELAY
1
Ignition switch in position 0.
2
Disconnect WOT relay C165.
3
Ignition switch in position II.

4
Measure the voltage between the WOT relay, connector C165, pin 1, circuit 94S-CA11 (VT/YE), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C14.
No
LOCATE and RECTIFY open circuit in circuit 94S-CA11 (VT/YE) between the WOT relay and fuse F28 (vehicles built before 02/00) or F30 (vehicles built from 02/00) with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C14: CHECK THE VOLTAGE SUPPLY TO THE A/C WOT RELAY

1
Measure the voltage between the WOT relay, connector C165, pin 5, circuit 14S-CA12 (VT/BU), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C17.
No
GO to C15.
C15: CHECK THE VOLTAGE SUPPLY TO THE DUAL PRESSURE SWITCH
1
Ignition switch in position 0.
2
Disconnect Dual pressure switch C96.
3
Ignition switch in position II.

4
Measure the voltage between the dual pressure switch, connector C96, pin 4, circuit 14-CA38 (VT), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C16.
No
LOCATE and RECTIFY open circuit in circuit 14-CA38 (VT) between the dual pressure switch and fuse F29 (vehicles built before 02/00) or F31 (vehicles built from 02/00) with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C16: CHECK THE DUAL PRESSURE SWITCH
1
Ignition switch in position 0.

2
Measure the resistance between the dual pressure switch, connector C96, pin 2 and pin 4, component side.

Is less than 2 Ohm displayed?
Yes
LOCATE and RECTIFY open circuit in circuit 14S-CA12 (VT/BU) between the WOT relay and the dual pressure switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
No
CHECK and if necessary RENEW the dual pressure switch. If the dual pressure switch is OK, CHECK and if necessary REPAIR the refrigerant circuit. CHECK the operation of the system.
C17: CHECK THE A/C COMPRESSOR

1
Use a cable link to bridge the WOT relay, connector C165, between pin 5, circuit 14S-CA12 (VT/BU) and pin 3, circuit 14S-CA1 (VT/BU), wiring harness side.

Is the A/C compressor on?
Yes
GO to C20.
No
GO to C18.
C18: CHECK THE VOLTAGE SUPPLY TO THE A/C COMPRESSOR CLUTCH
1
Ignition switch in position 0.
2
Disconnect A/C compressor clutch C94.
3
Connect WOT relay C165.
4
Ignition switch in position II.
5
Switch on the heater blower.
6
Switch on the air conditioning.

7
Measure the voltage between the A/C compressor clutch, connector C94, circuit 14S-CA6 (VT/YE), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C19.
No
LOCATE and RECTIFY open circuit in circuit 14S-CA6 (VT/YE) between the WOT relay and the A/C compressor clutch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C19: CHECK THE GROUND CONNECTION OF THE A/C COMPRESSOR CLUTCH
1
Ignition switch in position 0.

2
Measure the resistance between the A/C compressor clutch, connector C94, circuit 31-CA6 (BK), wiring harness side and ground.

Is less than 2 Ohm displayed?
Yes
CHECK and if necessary RENEW the A/C compressor clutch. CHECK the operation of the system.
No
LOCATE and RECTIFY open circuit in circuit 31-CA6 (BK) between the A/C compressor clutch and ground connection G11. CHECK the operation of the system.
C20: CHECK THE CONNECTION BETWEEN THE WOT RELAY AND THE PCM.
1
Switch on the heater blower.
2
Switch on the air conditioning.

3
Measure the resistance between the WOT relay, socket C165, pin 2, circuit 31S-CA11 (BK/YE), wiring harness side and ground.

Is less than 1000 Ohm displayed?
Yes
CHECK and if necessary RENEW the WOT relay. CHECK the operation of the system
No
GO to C21.
C21: CHECK THE VOLTAGE SUPPLY TO THE A/C RELAY
1
Disconnect A/C relay C162.
2
Ignition switch in position II.

3
Measure the voltage between the A/C relay, connector C162, pin 2, circuit 94S-CA66 (VT/OG), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C22.
No
LOCATE and RECTIFY open circuit in circuit 94S-CA66 (VT/OG) between the A/C relay and fuse F28 (vehicles built before 02/00) or F30 (vehicles built from 02/00) with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C22: CHECK THE VOLTAGE SUPPLY TO THE A/C RELAY

1
Measure the voltage between the A/C relay, connector C162, pin 3, circuit 14S-CA67 (VT/BK), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C23.
No
LOCATE and RECTIFY open circuit in circuit 14S-CA67 (VT/BK) between the A/C relay and fuse F29 (vehicles built before 02/00) or F31 (vehicles built from 02/00) with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C23: CHECK THE GROUND CONNECTION OF THE A/C RELAY
1
Switch on the heater blower.
2
Switch on the air conditioning.

3
Measure the voltage between the A/C relay, socket C162, pin 1, circuit 31S-CA66 (BK/RD), wiring harness side and ground.

Is less than 2 V displayed?
Yes
GO to C28.
No
GO to C24.
C24: CHECK THE CONNECTION BETWEEN THE A/C RELAY AND THE HEATER CONTROL MODULE
1
Ignition switch in position 0.
2
Disconnect Heater control module C41.

3
Measure the resistance between the A/C relay, socket C162, pin 1, circuit 31S-CA66 (BK/RD), wiring harness side and the heater control module, connector C41, pin 11, circuit 31S-CA66 (BK/RD), wiring harness side.

Is less than 2 Ohm displayed?
Yes
GO to C25.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA66 (BK/RD) between the A/C relay and the heater control module with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C25: CHECK THE VOLTAGE SUPPLY TO THE HEATER CONTROL MODULE
1
Ignition switch in position II.

2
Measure the voltage between the heater control module, connector C41, pin 12, circuit 14-CA45A (VT), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C26.
No
LOCATE and RECTIFY open circuit in circuit 14-CA45A (VT) between the heater control module and fuse F13 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C26: CHECK THE VOLTAGE SUPPLY TO THE HEATER CONTROL MODULE

1
Measure the voltage between the heater control module, connector C41, pin 2, circuit 29-CA83 (OG/GN), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C27.
No
LOCATE and RECTIFY open circuit in circuit 29-CA83 (OG/GN) between the heater control module and fuse F2 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C27: CHECK THE CONTROL VOLTAGE FROM THE HEATER BLOWER SWITCH
1
Switch on the heater blower.

2
Measure the voltage between the heater control module, connector C41, pin 7, circuit 31S-CA25 (BK/GN), wiring harness side and ground.

Is battery voltage displayed?
Yes
CHECK and if necessary RENEW the heater control module. CHECK the operation of the system
No
LOCATE and RECTIFY open circuit in circuit 31S-CA25 (BK/GN) between the heater control module and the heater blower switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C28: CHECK THE A/C CONTROL CIRCUIT

1
Use a cable link to bridge the A/C relay, connector C162, between pin 5, circuit 14S-CA17 (VT/OG) and pin 3, circuit 14-CA67 (VT/BK), wiring harness side.

Is the A/C compressor on?
Yes
CHECK and if necessary RENEW the A/C relay. CHECK the operation of the system
No
GO to C29.
C29: CHECK THE VOLTAGE SUPPLY TO THE A/C COMPRESSOR SWITCH
1
Ignition switch in position 0.
2
Disconnect A/C compressor switch C95.
3
Connect A/C relay C162.
4
Ignition switch in position II.

5
Measure the voltage between the A/C compressor switch, connector C95, pin 1, circuit 14S-CA17 (VT/OG), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C30.
No
LOCATE and RECTIFY open circuit in circuit 14S-CA17 (VT/OG) between the A/C relay and the A/C compressor switch with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C30: CHECK THE A/C COMPRESSOR SWITCH
1
Ignition switch in position 0.

2
Measure the resistance between the A/C compressor switch, connector C95, pin 1 and pin 4, component side.

Is less than 2 Ohm displayed?
Yes
Vehicles with PCM: GO to C31.
Vehicles with EEC: GO to C33.
No
CHECK and if necessary RENEW the A/C compressor switch. If the A/C compressor switch is OK, CHECK and if necessary CORRECT the quantity of refrigerant in the system. CHECK the operation of the system.
C31: CHECK THE CONTROL LINE TO THE PCM
1
Disconnect PCM (C159).
2
Connect A/C compressor switch C95.
3
Ignition switch in position II.

4
Measure the voltage between the PCM, connector C159, pin 41, circuit 14S-PC72 (VT/BU), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C32.
No
LOCATE and RECTIFY open circuit in circuit 14S-PC72 (VT/BU) between the A/C compressor switch and the PCM with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C32: CHECK THE CONTROL LINE OF THE WOT RELAY

1
Measure the voltage between the PCM, connector C159, pin 69, circuit 31S-CA11 (BK/YE), wiring harness side and ground.

Is battery voltage displayed?
Yes
CHECK and if necessary RENEW the PCM. CHECK the operation of the system
No
LOCATE and RECTIFY open circuit in circuit 31S-CA11 (BK/YE) between the WOT relay and the PCM with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C33: CHECK THE CONTROL LINE TO THE EEC
1
Disconnect EEC C1159.
2
Connect A/C compressor switch C95.
3
Ignition switch in position II.

4
Measure the voltage between the EEC, connector C1159, pin 10, circuit 14S-PC72 (VT/BU), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to C34.
No
LOCATE and RECTIFY open circuit in circuit 14S-PC72 (VT/BU) between the A/C compressor switch and the EEC with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
C34: CHECK THE CONTROL LINE OF THE WOT RELAY

1
Measure the voltage between the EEC, connector C1159, pin 54, circuit 31S-CA11 (BK/YE), wiring harness side and ground.

Is battery voltage displayed?
Yes
CHECK and if necessary RENEW the EEC. CHECK the operation of the system
No
LOCATE and RECTIFY open circuit in circuit 31S-CA11 (BK/YE) between the WOT relay and the EEC with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.

PINPOINT TEST D : MALFUNCTION OF THE AIR RECIRCULATION VALVE
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
D1: CHECK FUSE F2
1
Ignition switch in position 0.
2
CHECK Fuse F2 (CJB).
3
Check fuse F2 (10 A)

Is the fuse OK?
Yes
GO to D2.
No
RENEW fuse F2 (10 A). CHECK the operation of the system. If the fuse blows again immediately after installing, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
D2: MEASURE THE VOLTAGE AT FUSE F2
1
Connect Fuse F2 (CJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F2 (10 A) and ground.

Is battery voltage displayed?
Yes
GO to D3.
No
REPAIR the voltage supply to fuse F2 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D3: CHECK FUSE F13
1
Ignition switch in position 0.
2
CHECK Fuse F13 (CJB).
3
Check fuse F13 (15 A)

Is the fuse OK?
Yes
GO to D4.
No
RENEW fuse F13 (15 A). CHECK the operation of the system. If the fuse blows again immediately after installing, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
D4: CHECK VOLTAGE AT FUSE F13
1
Connect Fuse F13 (CJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F13 (15 A) and ground.

Is battery voltage displayed?
Yes
GO to D5.
No
REPAIR the voltage supply to fuse F13 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D5: CHECK FUSE F16
1
Ignition switch in position 0.
2
CHECK Fuse F16 (CJB).
3
Check fuse F16 (30 A)

Is the fuse OK?
Yes
GO to D6.
No
RENEW fuse F16 (30 A). CHECK the operation of the system. If the fuse blows again immediately after installing, LOCATE and RECTIFY short circuit to ground with the aid of the Wiring Diagrams Binder.
D6: MEASURE THE VOLTAGE AT FUSE F16
1
Connect Fuse F16 (CJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F16 (30 A) and ground.

Is battery voltage displayed?
Yes
Vehicles built before 02/99: GO to D7.
Vehicles built from 02/99 GO to D11.
No
REPAIR the voltage supply to fuse F16 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D7: CHECK THE VOLTAGE SUPPLY TO THE AIR RECIRCULATION VALVE CONTROL MOTOR
1
Ignition switch in position 0.
2
Disconnect Air recirculation valve control motor C222.
3
Ignition switch in position II.

4
Measure the voltage between the air recirculation valve control motor, connector C222, pin 1, circuit 14-CA76 (VT), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to D8.
No
LOCATE and RECTIFY open circuit in circuit 14-CA76 (VT) between the air recirculation valve control motor and fuse F16 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D8: CHECK THE GROUND CONNECTION OF THE AIR RECIRCULATION VALVE CONTROL MOTOR
1
Ignition switch in position 0.

2
Measure the resistance between the air recirculation valve control motor, connector C222, pin 3, circuit 31-CA76 (BK), wiring harness side and ground.

Is less than 2 Ohm displayed?
Yes
GO to D9.
No
LOCATE and RECTIFY open circuit in circuit 31-CA76 (BK) between the air recirculation valve control motor and ground connection G13 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D9: CHECK THE VOLTAGE SUPPLY TO THE AIR RECIRCULATION VALVE CONTROL MOTOR
1
Ignition switch in position II.
2
Set the heater control module to "Air recirculation".

3
Measure the voltage between the air recirculation valve control motor, connector C222, pin 2, circuit 31S-CA76 (BK/OG), wiring harness side and ground.

Is battery voltage displayed?
Yes
CHECK and if necessary RENEW the air recirculation valve control motor. CHECK the operation of the system.
No
GO to D10.
D10: CHECK THE CONTROL LINE OF THE AIR RECIRCULATION VALVE CONTROL MOTOR
1
Ignition switch in position 0.
2
Disconnect Heater control module C41.

3
Measure the resistance between the air recirculation valve control motor, connector C222, pin 2, circuit 31S-CA76 (BK/OG) and the heater control module, connector C41, pin 9, circuit 31S-CA76 (BK/OG), wiring harness side.

Is less than 2 Ohm displayed?
Yes
GO to D15.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA76 (BK/OG) between the air recirculation valve control motor and the heater control module with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D11: CHECK THE VOLTAGE SUPPLY TO THE AIR RECIRCULATION VALVE CONTROL MOTOR
1
Ignition switch in position 0.
2
Disconnect Air recirculation valve control motor C1222.
3
Ignition switch in position II.

4
Measure the voltage between the air recirculation valve control motor, connector C1222, pin 5, circuit 14-CA76 (VT), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to D12.
No
LOCATE and RECTIFY open circuit in circuit 14-CA76 (VT) between the air recirculation valve control motor and fuse F16 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D12: CHECK THE GROUND CONNECTION OF THE AIR RECIRCULATION VALVE CONTROL MOTOR
1
Ignition switch in position 0.

2
Measure the voltage between the air recirculation valve control motor, connector C1222, pin 4, circuit 31S-CA76 (BK/BU), wiring harness side and ground.

Is less than 2 Ohm displayed?
Yes
GO to D13.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA76 (BK/BU) between the air recirculation valve control motor and ground connection G13 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D13: CHECK THE VOLTAGE SUPPLY TO THE AIR RECIRCULATION VALVE CONTROL MOTOR
1
Ignition switch in position II.
2
Set the heater control module to "Air recirculation".

3
Measure the voltage between the air recirculation valve control motor, connector C1222, pin 6, circuit 31S-CA76 (BK/OG), wiring harness side and ground.

Is battery voltage displayed?
Yes
CHECK and if necessary RENEW the air recirculation valve control motor. CHECK the operation of the system.
No
GO to D14.
D14: CHECK THE CONTROL LINE OF THE AIR RECIRCULATION VALVE CONTROL MOTOR
1
Ignition switch in position 0.
2
Disconnect Heater control module C41.

3
Measure the resistance between the air recirculation valve control motor, connector C1222, pin 6, circuit 31S-CA76 (BK/OG) and the heater control module, connector C41, pin 9, circuit 31S-CA76 (BK/OG), wiring harness side.

Is less than 2 Ohm displayed?
Yes
GO to D15.
No
LOCATE and RECTIFY open circuit in circuit 31S-CA76 (BK/OG) between the air recirculation valve control motor and the heater control module with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D15: CHECK THE VOLTAGE SUPPLY TO THE HEATER CONTROL MODULE
1
Ignition switch in position II.

2
Measure the voltage between the heater control module, connector C41, pin 12, circuit 14-CA45A (VT), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to D16.
No
LOCATE and RECTIFY open circuit in circuit 14-CA45A (VT) between the heater control module and fuse F13 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D16: CHECK THE VOLTAGE SUPPLY TO THE HEATER CONTROL MODULE

1
Measure the voltage between the heater control module, connector C41, pin 2, circuit 29-CA83 (OG/GN), wiring harness side and ground.

Is battery voltage displayed?
Yes
GO to D17.
No
LOCATE and RECTIFY open circuit in circuit 29-CA83 (OG/GN) between the heater control module and fuse F2 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.
D17: CHECK THE GROUND CONNECTION OF THE HEATER CONTROL MODULE
1
Ignition switch in position 0.

2
Measure the resistance between the heater control module, connector C41, pin 6, circuit 91-CA83 (BK/RD), wiring harness side and ground.

Is less than 2 Ohm displayed?
Yes
CHECK and if necessary RENEW the heater control module. CHECK the operation of the system
No
LOCATE and RECTIFY open circuit in circuit 91-CA83 (BK/RD) between the heater control module and ground connection G4 with the aid of the Wiring Diagrams Binder. CHECK the operation of the system.

Component Check

Air conditioning WOT cut-off relay

  1. Check the normally open contact in the open position.
    • Measure the resistance between pin 3 and pin 5.
    • Is the resistance more than 10000 Ohm? If yes, go to 2. If no, renew the air conditioning shut-off relay.

  1. Check the normally open contact in the closed position.
    • Connect with test cables:

        • 1. C165 pin 1 with battery positive terminal.

        2. C165 pin 2 with battery negative terminal.

    • Measure the resistance at the socket connections between pin 3 and pin 5.
    • Does the relay switch (audible click) when battery voltage is applied and is the resistance less than 5 Ohm? If yes, then the relay is OK. Of no, renew the relay.

Air conditioning relay

  1. Check the normally open contact in the open position.
    • Measure the resistance between pin 3 and pin 5.
    • Is the resistance more than 10000 Ohm? If yes, go to 2. If no, renew the air conditioning relay.

  1. Check the normally open contact in the closed position.
    • Connect with test cables:

        • 1. C162 pin 1 to battery positive terminal.

        2. C162 pin 2 to battery negative terminal.

    • Measure the resistance at the socket connection between pin 3 and pin 5.
    • Does the relay switch (audible click) when battery voltage is applied and is the resistance less than 5 Ohm? If yes, then the relay is OK. If not, renew the relay.

Fan motor relay (high speed)

  1. Check the normally open contact in the open position.
    • Measure the resistance between pin 3 and pin 5.
    • Is the resistance more than 10000 Ohm? If yes, go to 2. If no, renew the fan motor relay (high speed).

  1. Check the normally open contact in the closed position.
    • Connect with test cables:

        • 1. C165 pin 2 with battery positive terminal.

        2. C165 pin 1 with battery negative terminal.

    • Measure the resistance at the socket connection between pin 3 and pin 5.
    • Does the relay switch (audible click) when battery voltage is applied and is the resistance less than 5 Ohm? If yes, then the relay is OK. Of no, renew the relay.

Refrigerant Circuit

Workshop Equipment

Servicing unit/pressure gauges

Stopwatch

Electronic leak tester

Leak test

Test all components and refrigerant lines with an electronic leak tester. Follow the equipment manufacturer's instructions.

If necessary switch on the motor and the air conditioning to locate any small leaks in the high-pressure lines.

NOTE:
NOTE:Heavy oil contamination on lines or components is an indication of leaks.

Leaks

If a leakage is detected: eliminate the leak, renew any faulty components and drain and refill the air conditioning system.

Pinpoint Test

Three values are used for the fault diagnosis:

  • Low-pressure
  • High-pressure
  • Compressor switching cycles (on/off)

Connecting the testing equipment

The following requirements must be met in order to carry out an accurate test:

  • Close both of the manual valves on the pressure gauges. Connect the pressure gauges to the high-pressure and the low-pressure side of the air conditioning system.
  • Start the engine, set the air conditioning to maximum cooling and air recirculation, and set the blower to maximum power.
  • Run the engine at 1500 rev/min.

Specified values for high and low-pressure

The measured values for high and low-pressure depend on the outside temperature. This is shown in the diagram and the table.

The area between the two curves corresponds to the tolerance range. The measured value must lie in this range.

Specified values for high-pressure

 
Item
Part Number
Description
1
-
High-pressure (bar)
2
-
Outside temperature (°C)

Specified values for low-temperature

 
Item
Part Number
Description
1
-
Low-pressure (bar)
2
-
Outside temperature (°C)

Required values: switching cycles

The following three diagrams show the required values for the compressor switching cycles. Measure the cycles using a stopwatch and make a note of the result.

If the measured values are outside the tolerance range in any of the diagrams then a fault is present. Refer to the Symptom Chart in this section.

NOTE:
NOTE:The total cycle time is obtained by adding the on-time to the off-time.

Specified values for on-time

 
Item
Part Number
Description
1
-
On-time (s)
2
-
Outside temperature (°C)

Specified values for off-time

 
Item
Part Number
Description
1
-
Off-time (s)
2
-
Outside temperature (°C)

Specified values for total cycle time

 
Item
Part Number
Description
1
-
Total cycle time (s)
2
-
Outside temperature (°C)

Check the on/off-cycles

The following conditions must be met before checking the switching cycle:

  1. Connect the pressure gauges to the high and low-pressure side of the air conditioning system.
  1. Start the engine end allow it to run for approx. 10 min at 1500 rev/min.
  1. Set the air conditioning to maximum cooling and air recirculation.
  1. Set the blower to maximum power.
  1. Adjust the interior temperature to approx. 22 °C.
  1. Measure the switching cycles using a stopwatch and make a note of the results.
  1. Read off the pressure from the pressure gauges, make a note of the values and compare them with the required values in the diagrams.

As an example, after comparison with the diagrams the following five faults could be present. Next compare these statements with those in the Symptom Chart on the next page and read off the cause of the fault.

Example:

  • High-pressure - too low
  • Low-pressure - normal
  • Switching cycles per minute - too many
  • Clutch on-time - too short
  • Clutch off-time - too short

Fault present: not enough refrigerant in the system.

Symptom Chart - Refrigerant Circuit

High- pressure Low- pressure Clutch cycle times: cycle Clutch cycle times: on-time Clutch cycle times: off-time Fault cause/action
too high too high compressor running constantly compressor running constantly compressor running constantly Condenser contaminated
too high normal to too high compressor running constantly compressor running constantly compressor running constantly Engine overheated
normal to too high normal compressor running constantly compressor running constantly compressor running constantly Air or contaminants in the circuit. Too much refrigerant in the system.
normal too high compressor running constantly compressor running constantly compressor running constantly Fixed orifice tube, O-rings damaged or leaking
normal normal too slow too long or constantly normal or not at all Contaminants in the circuit or too much refrigerant oil
normal too low too slow too long too long Low-pressure switch faulty
normal to too low too high compressor running constantly compressor running constantly compressor running constantly Compressor faulty
normal to too low normal to too high compressor running constantly compressor running constantly compressor running constantly Low-pressure line blocked
normal to too low normal too fast too short normal Evaporator blocked
normal to too low normal too fast too short normal to too long Condenser, fixed orifice tube or high-pressure line blocked
normal to too low normal too fast too short too short Not enough refrigerant in the system
normal to too low normal too fast too short too long Evaporator input line blocked
normal to too low too low compressor running constantly compressor running constantly compressor running constantly Low-pressure line
- - irregular operation or inoperative irregular operation or inoperative irregular operation or inoperative Low-pressure switch contacts dirty or permanently open. Connector of low-pressure switch or of compressor clutch dirty or damaged.

General Procedures > < Climate Control System