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General Procedures > < 412-00 Climate Control System - General Information|Specifications

Focus RS 2003 (09.2002-)

Climate Control System - General Information - Climate Control System Focus RS 2003 (09/2002-)
Diagnosis and Testing

Refer to Wiring Diagrams Section 412-00, for schematic and connector information.

Special Tool(s)

Terminal Probe Kit

418-S035
General Equipment
Digital multimeter
Worldwide Diagnostic System (WDS)
Refrigerant centre

Inspection and Checking

  1. VERIFY customer concern.
  1. Visually CHECK for any obvious mechanical or electrical damage.

Visual Inspection

Mechanical Electrical
  • Drive belt
  • Refrigerant lines
  • Condenser core
  • Fuses
  • Wiring harness
  • Connectors
  1. RECTIFY any obvious causes for a concern found during the visual inspection before performing any further tests. CHECK the operation of the system.
  1. If the concern persists after the visual inspection, PERFORM a fault diagnosis on the electronic engine management with WDS and RECTIFY any displayed faults in accordance with the displayed fault description. CHECK the operation of the system.
  1. For vehicles with no stored faults, PROCEED in accordance with the Symptom Chart according to the fault symptom.

Symptom Chart

Symptom Chart

Symptom Possible Sources Action
Heater blower motor inoperative / partly inoperative
*
Fuse(s).
*
Circuit(s).
*
Heater blower motor.
*
Heater blower switch.
*
Heater blower motor variable resistor.
*
GO to Pinpoint Test A.
Heater blower motor running continuously
*
Circuit(s).
*
Heater blower switch.
*
GO to Pinpoint Test B.
Malfunction of the air recirculation flap
*
Circuit(s).
*
Air recirculation flap.
*
Air recirculation flap servo motor.
*
Heater control module.
*
GO to Pinpoint Test C.
Air conditioning inoperative (heater blower function OK)
*
Fuse(s).
*
Circuit(s).
*
A/C compressor clutch diode.
*
A/C compressor clutch.
*
A/C wide open throttle (WOT) relay.
*
Refrigerant quantity.
*
Dual pressure switch.
*
A/C compressor switch.
*
Powertrain control module (PCM).
*
Heater control module.
*
GO to Pinpoint Test D.
Inadequate cooling power from the air conditioning (A/C compressor clutch function OK)
*
Cooling fan not operating properly
*
Refrigerant quantity
*
Refrigerant circuit
*
CHECK the engine management with WDS.
*
CHECK the refrigerant quantity/circuit with the R-134a refrigerant centre and REPAIR the system as required.

System Checks

PINPOINT TEST A : HEATER BLOWER MOTOR INOPERATIVE / PARTLY INOPERATIVE
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
A1: CHECK ALL SPEED SETTINGS OF THE HEATER BLOWER MOTOR
1
Ignition switch in position II.
2
Switch the heater blower switch through all settings.

Is the heater blower motor inoperative in all switch positions?
Yes
GO to A2.
No
- The heater blower motor is only inoperative in switch position 4:GO to A8.
- The heater blower motor is inoperative in switch positions 1, 2 and/or 3:GO to A9.
A2: CHECK FUSE F64
1
Ignition switch in position 0.
2
CHECK fuse F64 (BJB).

Is the fuse OK?
Yes
GO to A3.
No
RENEW fuse F64 (30 A). CHECK the operation of the system. If the fuse blows again, LOCATE and REPAIR the short to ground using the Wiring Diagrams.
A3: CHECK THE VOLTAGE AT FUSE F64
1
Connect fuse F64 (BJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F64 (30 A) and ground.

Does the meter display battery voltage?
Yes
GO to A4.
No
REPAIR the voltage supply to fuse F64 using the Wiring Diagrams. CHECK the operation of the system.
A4: CHECK THE VOLTAGE AT THE HEATER BLOWER MOTOR
1
Ignition switch in position 0.
2
Disconnect connector C789 from heater blower motor.
3
Ignition switch in position II.

4
Measure the voltage between the heater blower motor, connector C789, pin 1, circuit 15-FA18 (GN/OG), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to A5.
No
LOCATE and REPAIR the open circuit between the heater blower motor and fuse F64 using the Wiring Diagrams. CHECK the operation of the system.
A5: CHECK THE GROUND CONNECTION OF THE HEATER BLOWER MOTOR
1
Ignition switch in position 0.
2
Set the heater blower switch to position 4.

3
Measure the resistance between the heater blower motor, connector C789, pin 2, circuit 31S-FA18 (BK/RD), wiring harness side and ground.

Is a resistance of less than 2 Ohms registered?
Yes
RENEW the heater blower motor. CHECK the operation of the system.
No
GO to A6.
A6: CHECK THE CIRCUIT BETWEEN THE HEATER BLOWER MOTOR AND THE HEATER BLOWER SWITCH
1
Disconnect connector C469 from heater blower switch.

2
Measure the resistance between the heater blower motor, connector C789, pin 2, circuit 31S-FA18 (BK/RD), wiring harness side and the heater blower switch, connector C469, pin 6, circuit 31S-FA33 (BK/OG), wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
GO to A7.
No
LOCATE and REPAIR the break in circuit 31S-FA18 (BK/RD) between the heater blower motor and soldered connection S24 using the Wiring Diagrams. CHECK the operation of the system.
A7: CHECK THE GROUND CONNECTION OF THE HEATER BLOWER SWITCH

1
Measure the resistance between the heater blower switch, connector C469, pin 2, circuit 31-FA25 (BK), wiring harness side and ground.

Is a resistance of less than 2 Ohms registered?
Yes
RENEW the heater blower switch. CHECK the operation of the system.
No
LOCATE and REPAIR the open circuit between the heater blower switch and ground connection G14 using the Wiring Diagrams. CHECK the operation of the system.
A8: CHECK THE CIRCUIT BETWEEN THE HEATER BLOWER MOTOR AND THE HEATER BLOWER SWITCH
1
Ignition switch in position 0.
2
Disconnect connector C469 from heater blower switch.
3
Disconnect connector C789 from heater blower motor.

4
Measure the resistance between the heater blower motor, connector C789, pin 2, circuit 31S-FA18 (BK/RD), wiring harness side and the heater blower switch, connector C469, pin 6, circuit 31S-FA33 (BK/OG), wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
RENEW the heater blower switch. CHECK the operation of the system.
No
LOCATE and REPAIR the break in circuit 31S-FA33 (BK/OG) between soldered connection S24 and the heater blower switch using the Wiring Diagrams. CHECK the operation of the system.
A9: CHECK THE HEATER BLOWER SWITCH
1
Ignition switch in position 0.
2
Disconnect connector C469 from heater blower switch.
3
Ignition switch in position II.

4
Measure the voltage between the heater blower switch, connector C469, pin 5, circuit 31S-FA32 (BK/BU), wiring harness side and ground.
5
Measure the voltage between the heater blower switch, connector C469, pin 3, circuit 31S-FA31 (BK/YE), wiring harness side and ground.
6
Measure the voltage between the heater blower switch, connector C469, pin 1, circuit 31S-FA30 (BK/WH), wiring harness side and ground.

Is battery voltage measured in all cases?
Yes
RENEW the heater blower switch. CHECK the operation of the system.
No
GO to A10.
A10: CHECK THE CIRCUIT BETWEEN THE HEATER BLOWER MOTOR AND THE HEATER BLOWER VARIABLE RESISTOR.
1
Ignition switch in position 0.
2
Disconnect connector C470 from heater blower variable resistor.
3
Ignition switch in position II.

4
Measure the voltage between the heater blower variable resistor, connector C470, pin 1, circuit 31S-FA33 (BK/OG), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to A11.
No
LOCATE and REPAIR the break in the circuit between soldered connection S24 and the heater blower variable resistor using the Wiring Diagrams. CHECK the operation of the system.
A11: CHECK THE CIRCUIT BETWEEN THE HEATER BLOWER VARIABLE RESISTOR AND THE HEATER BLOWER SWITCH - POSITION 3
1
Ignition switch in position 0.

2
Measure the resistance between the heater blower variable resistor, connector C470, pin 4, circuit 31S-FA32 (BK/BU), wiring harness side and the heater blower switch, connector C469, pin 5, circuit 31S-FA32 (BK/BU), wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
GO to A12.
No
LOCATE and REPAIR the break in circuit 31S-FA32 (BK/BU) between the heater blower variable resistor and the heater blower switch using the Wiring Diagrams. CHECK the operation of the system.
A12: CHECK THE CIRCUIT BETWEEN THE HEATER BLOWER VARIABLE RESISTOR AND THE HEATER BLOWER SWITCH - POSITION 2

1
Measure the resistance between the heater blower variable resistor, connector C470, pin 2, circuit 31S-FA31 (BK/YE), wiring harness side and the heater blower switch, connector C469, pin 3, circuit 31S-FA31 (BK/YE), wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
GO to A13.
No
LOCATE and REPAIR the break in circuit 31S-FA31 (BK/YE) between the heater blower variable resistor and the heater blower switch using the Wiring Diagrams. CHECK the operation of the system.
A13: CHECK THE CIRCUIT BETWEEN THE HEATER BLOWER VARIABLE RESISTOR AND THE HEATER BLOWER SWITCH - POSITION 1

1
Measure the resistance between the heater blower variable resistor, connector C470, pin 3, circuit 31S-FA30 (BK/WH), wiring harness side and the heater blower switch, connector C469, pin 1, circuit 31S-FA30 (BK/WH), wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
RENEW the heater blower variable resistor. CHECK the operation of the system.
No
LOCATE and REPAIR the break in circuit 31S-FA30 (BK/WH) between the heater blower variable resistor and the heater blower switch using the Wiring Diagrams. CHECK the operation of the system.

PINPOINT TEST B : HEATER BLOWER MOTOR RUNNING CONTINUOUSLY
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
B1: CHECK THE HEATER BLOWER SWITCH
1
Ignition switch in position 0.
2
Disconnect connector C469 from heater blower switch.
3
Ignition switch in position II.

Does the heater blower motor run continuously?
Yes
GO to B2.
No
RENEW the heater blower switch. CHECK the operation of the system.
B2: CHECK THE CIRCUITS AT THE HEATER BLOWER VARIABLE RESISTOR
1
Ignition switch in position 0.
2
Disconnect connector C470 from heater blower variable resistor.
3
Ignition switch in position II.

Does the heater blower motor run continuously?
Yes
CHECK all circuits connected to soldered connection S24 for short to ground using the Wiring Diagrams and REPAIR any short circuit(s) found. CHECK the operation of the system.
No
CHECK all circuits between the heater blower variable resistor and the heater blower switch for short to ground using the Wiring Diagrams and REPAIR any short circuit(s) found. CHECK the operation of the system.

PINPOINT TEST C : MALFUNCTION OF THE AIR RECIRCULATION FLAP
NOTE:
NOTE:The air recirculation flap is actuated by means of a DC motor. This is activated for a maximum of 7 seconds by the heater control module following actuation of the recirculated air button. Opening and closing of the air recirculation flap is performed by reversing the polarity of the applied voltage.
NOTE:
NOTE:Recirculated air mode is not available if the air distribution control is set to "Defrost/demist windscreen".
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
C1: CHECK VOLTAGE AT AIR RECIRCULATION FLAP SERVO MOTOR
1
Ignition switch in position 0.
2
Disconnect connector C538 from air recirculation flap servo motor.
3
Ignition switch in position II.

4
Measure the voltage at the air recirculation flap servo motor, connector C538, between pin 2 and pin 4, wiring harness side.
5
Actuate the air recirculation switch several times during the measurement.

Is a voltage of approx. 11 V measured with alternating polarity?
Yes
CHECK the air recirculation flap for ease of movement and correct operation. If the air recirculation flap is mechanically OK, RENEW the air recirculation flap servo motor. CHECK the operation of the system.
No
GO to C2.
C2: CHECK THE CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE AIR RECIRCULATION FLAP SERVO MOTOR
1
Ignition switch in position 0.
2
Disconnect connector C380 from heater control module.

3
Measure the resistance between the heater control module, connector C380, pin 16, circuit 33-FA76 (YE/BU), wiring harness side and the air recirculation flap servo motor, connector C538, pin 2, circuit 33-FA76 (YE/BU) (RHD vehicles: circuit 32-FA76 (WH/BU), wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
GO to C3.
No
LOCATE and REPAIR the break in the circuit between the heater control module and the air recirculation flap servo motor using the Wiring Diagrams. CHECK the operation of the system.
C3: CHECK THE CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE AIR RECIRCULATION FLAP SERVO MOTOR

1
Measure the resistance between the heater control module, connector C380, pin 14, circuit 32-FA76 (WH/BU), wiring harness side and the air recirculation flap servo motor, connector C538, pin 4, circuit 32-FA76 (WH/BU) (RHD vehicles  : circuit 33-FA76 (YE/BU), wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
GO to C4.
No
LOCATE and REPAIR the break in the circuit between the heater control module and the air recirculation flap servo motor using the Wiring Diagrams. CHECK the operation of the system.
C4: CHECK THE CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE AIR RECIRCULATION FLAP SERVO MOTOR FOR SHORT TO VOLTAGE SUPPLY
1
Ignition switch in position II.

2
Measure the voltage between the heater control module, connector C380, pin 14, circuit 32-FA76 (WH/BU), wiring harness side and ground.
3
Measure the voltage between the heater control module, connector C380, pin 16, circuit 33-FA76 (YE/BU), wiring harness side and ground.

Is a voltage measured?
Yes
LOCATE and REPAIR the short to voltage in circuit 32-FA76 (WH/BU) or 33-FA76 (YE/BU) between the heater control module and the air recirculation flap servo motor using the Wiring Diagrams. CHECK the operation of the system.
No
GO to C5.
C5: CHECK THE CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE AIR RECIRCULATION FLAP SERVO MOTOR FOR SHORT TO GROUND
1
Ignition switch in position 0.

2
Measure the resistance between the heater control module, connector C380, pin 14, circuit 32-FA76 (WH/BU), wiring harness side and ground.
3
Measure the resistance between the heater control module, connector C380, pin 16, circuit 33-FA76 (YE/BU), wiring harness side and ground.

Is a resistance greater than 10,000 Ohm measured in both cases?
Yes
CHECK the heater control module and RENEW as necessary. CHECK the operation of the system.
No
LOCATE and REPAIR the short to ground in circuit 32-FA76 (WH/BU) or 33-FA76 (YE/BU) between the heater control module and the air recirculation flap servo motor using the Wiring Diagrams. CHECK the operation of the system.

PINPOINT TEST D : AIR CONDITIONING INOPERATIVE (HEATER BLOWER FUNCTION OK)
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
D1: CHECK FUSE F15
1
Ignition switch in position 0.
2
CHECK fuse F15 (BJB).

Is the fuse OK?
Yes
GO to D2.
No
RENEW fuse F15 (10 A). If the fuse blows again after switching on the air conditioning, CHECK the A/C compressor clutch diode and RENEW as necessary. If the diode is OK, LOCATE and REPAIR the short to ground using the Wiring Diagrams. CHECK the operation of the system.
D2: CHECK THE VOLTAGE AT FUSE F15
1
Connect fuse F15 (BJB).
2
Measure the voltage between fuse F15 (10 A) and ground.

Does the meter display battery voltage?
Yes
GO to D3.
No
REPAIR the voltage supply to fuse F15 using the Wiring Diagrams. CHECK the operation of the system.
D3: CHECK FUSE F36
1
CHECK fuse F36 (CJB).

Is the fuse OK?
Yes
GO to D4.
No
RENEW fuse F36 (7.5 A). If the fuse blows again, LOCATE and REPAIR the short to ground using the Wiring Diagrams. CHECK the operation of the system.
D4: CHECK THE VOLTAGE AT FUSE F36
1
Connect fuse F36 (CJB).
2
Measure the voltage between fuse F36 (7.5 A) and ground.

Does the meter display battery voltage?
Yes
GO to D5.
No
REPAIR the voltage supply to fuse F36 using the Wiring Diagrams. CHECK the operation of the system.
D5: CHECK FUSE F45
1
CHECK fuse F45 (CJB).

Is the fuse OK?
Yes
GO to D6.
No
RENEW fuse F45 (7.5 A). If the fuse blows again, LOCATE and REPAIR the short to ground using the Wiring Diagrams. CHECK the operation of the system.
D6: CHECK THE VOLTAGE AT FUSE F45
1
Connect fuse F45 (CJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F45 (7.5 A) and ground.

Does the meter display battery voltage?
Yes
GO to D7.
No
REPAIR the voltage supply to fuse F45 using the Wiring Diagrams. CHECK the operation of the system.
D7: CHECK THE VOLTAGE SUPPLY AT THE A/C SYSTEM WIDE OPEN THROTTLE RELAY (WOT)
1
Ignition switch in position 0.
2
Disconnect A/C WOT relay C1011 (BJB).

3
Measure the voltage between the A/C WOT relay, socket C1011, pin 3, circuit 15-FA38 (GN/RD), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to D8.
No
LOCATE and REPAIR the break in circuit 15-FA38 (GN/RD) between fuse F15 and the A/C WOT relay using the Wiring Diagrams. CHECK the operation of the system.
D8: CHECK THE CONTROL VOLTAGE AT THE A/C WOT RELAY
1
Ignition switch in position III.

2
Measure the voltage between the A/C WOT relay, socket C1011, pin 1, circuit 15-FA11 (GN/YE), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to D9.
No
LOCATE and REPAIR the break in circuit 15-FA11 (GN/YE) between soldered connection S117 and the A/C WOT relay using the Wiring Diagrams. CHECK the operation of the system.
D9: CHECK THE A/C COMPRESSOR CLUTCH CIRCUIT
1
Ignition switch in position 0.

2
Use a fused test cable (10 A) to bridge the A/C WOT relay, socket C1011, pins 3 and pin 5, wiring harness side.
3
Ignition switch in position III.
4
Check the operation of the A/C compressor clutch.

Is the A/C compressor operative?
Yes
GO to D12.
No
GO to D10.
D10: CHECK FOR OPEN CIRCUIT BETWEEN THE A/C WOT RELAY AND THE A/C COMPRESSOR CLUTCH
1
Ignition switch in position 0.
2
Disconnect connector C952 from A/C compressor clutch.

3
Measure the resistance between the A/C WOT relay, socket C1011, pin 5, wiring harness side and the A/C compressor clutch, connector C952, pin 1, circuit 15S-FA6 (GN/YE), wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
GO to D11.
No
LOCATE and REPAIR the open circuit between the A/C WOT relay and the A/C compressor clutch using the Wiring Diagrams. CHECK the operation of the system.
D11: CHECK THE GROUND CONNECTION OF THE A/C COMPRESSOR CLUTCH

1
Measure the resistance between the A/C compressor clutch, connector C952, pin 2, circuit 31-FA6 (BK), wiring harness side and ground.

Is a resistance of less than 2 Ohms registered?
Yes
RENEW the A/C compressor clutch. CHECK the operation of the system.
No
LOCATE and REPAIR the break in the circuit between the A/C compressor clutch and ground connection G56 using the Wiring Diagrams. CHECK the operation of the system.
D12: CHECK THE GROUND CONNECTION OF THE A/C WOT RELAY
1
Switch on the heater blower.
2
Switch on the air-conditioning system.

CAUTION:
CAUTION:It is imperative that a test lamp with a nominal voltage of 12 V and a nominal power rating of 1.2 W is used during the following test. Otherwise the PCM could be damaged, or the test results could be incorrect.
3
Use a test lamp (12 V, 1.2 W) to check the voltage at the A/C WOT relay, socket C1011, between pin 1 and pin 2, wiring harness side.

Does the test lamp illuminate?
Yes
RENEW the A/C WOT relay. CHECK the operation of the system.
No
GO to D13.
D13: CHECK THE REFRIGERANT QUANTITY
1
Ignition switch in position 0.
2
Check the quantity of refrigerant in the system.REFER to Section  412-00 Climate Control System - General Information.

Is the refrigerant quantity in accordance with manufacturer's specifications?
Yes
GO to D14.
No
FILL the system with the correct quantity of refrigerant. CHECK the system for leaks and CHECK the operation of the system.
D14: CHECK THE CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE PCM FOR SHORT TO VOLTAGE SUPPLY
1
Disconnect connector C380 from heater control module.
2
Disconnect connector C415 from PCM.
3
Ignition switch in position II.

4
Measure the voltage between the heater control module, connector C380, pin 9, circuit 15S-FA38 (GN/RD), wiring harness side and ground.

Is a voltage measured?
Yes
LOCATE and REPAIR the short to voltage supply in the circuit between the heater control module and the PCM using the Wiring Diagrams. CHECK the operation of the system.
No
GO to D15.
D15: CHECK THE CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE PCM FOR SHORT TO GROUND
1
Ignition switch in position 0.

2
Measure the resistance between the heater control module, connector C380, pin 9, circuit 15S-FA38 (GN/RD), wiring harness side and ground.

Is a resistance of less than 10,000 Ohms registered?
Yes
LOCATE and REPAIR the short to ground in the circuit between the heater control module and the PCM using the Wiring Diagrams. CHECK the operation of the system.
No
GO to D16.
D16: CHECK THE VOLTAGE AT THE DUAL PRESSURE SWITCH
1
Connect connector C380 to heater control module.
2
Connect connector C415 to PCM.
3
Disconnect connector C882 from dual pressure switch.
4
Ignition switch in position III.
5
Switch on the heater blower.
6
Switch on the air-conditioning system.

7
Measure the voltage between the dual pressure switch, connector C882, pin 1, circuit 15S-FA38 (GN/RD), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to D17.
No
GO to D24.
D17: CHECK THE DUAL PRESSURE SWITCH
1
Ignition switch in position 0.

2
Measure the resistance at the dual pressure switch, connector C882, between pin 1 and pin 4, component side.

Is a resistance of less than 2 Ohms registered?
Yes
GO to D18.
No
RENEW the dual pressure switch. CHECK the operation of the system.
D18: CHECK THE VOLTAGE AT THE A/C COMPRESSOR SWITCH
1
Connect connector C882 to dual pressure switch.
2
Disconnect connector C692 from A/C compressor switch.
3
Ignition switch in position III.
4
Switch on the heater blower.
5
Switch on the air-conditioning system.

6
Measure the voltage between the A/C compressor switch, connector C692, pin 1, circuit 15-FA17 (GN/OG), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to D19.
No
LOCATE and REPAIR the break in circuit 15S-FA17 (GN/OG) between the dual pressure switch and the A/C compressor switch using the Wiring Diagrams. CHECK the operation of the system.
D19: CHECK THE A/C COMPRESSOR SWITCH
1
Ignition switch in position 0.

2
Measure the resistance at the A/C compressor switch, connector C692, between pin 1 and pin 4, component side.

Is a resistance of less than 2 Ohms registered?
Yes
GO to D20.
No
RENEW the A/C compressor switch. CHECK the operation of the system.
D20: CHECK FOR OPEN CIRCUIT BETWEEN THE A/C COMPRESSOR SWITCH AND THE POWER TRAIN CONTROL MODULE (PCM)
1
Disconnect connector C415 from PCM.

2
Measure the resistance between PCM, connector C415, pin 41, circuit 15S-RE8 (GN/YE), wiring harness side and A/C compressor switch, connector C692, pin 4, circuit 15S-RE8 (GN/YE), wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
GO to D21.
No
LOCATE and REPAIR the break in circuit 15S-RE8 (GN/YE) between the A/C compressor switch and the PCM using the Wiring Diagrams. CHECK the operation of the system.
D21: CHECK THE CIRCUIT BETWEEN THE A/C WOT RELAY AND THE PCM FOR SHORT TO VOLTAGE SUPPLY
1
Ignition switch in position II.

2
Measure the voltage between the PCM, connector C415, pin 69, circuit 31S-FA11 (BK/YE), wiring harness side and ground.

Is a voltage measured?
Yes
LOCATE and REPAIR the short to voltage supply in circuit 31S-FA11 (BK/YE) between the A/C WOT relay and the PCM using the Wiring Diagrams. CHECK the operation of the system.
No
GO to D22.
D22: CHECK THE CIRCUIT BETWEEN THE A/C WOT RELAY AND THE PCM FOR SHORT TO GROUND
1
Ignition switch in position 0.

2
Measure the voltage between the PCM, connector C415, pin 69, circuit 31S-FA11 (BK/YE), wiring harness side and ground.

Is a resistance of less than 10,000 Ohms registered?
Yes
LOCATE and REPAIR the short to ground in circuit 31S-FA11 (BK/YE) between the A/C WOT relay and the PCM using the Wiring Diagrams. CHECK the operation of the system.
No
GO to D23.
D23: CHECK FOR OPEN CIRCUIT BETWEEN THE A/C WOT RELAY AND THE PCM

1
Measure the resistance between the PCM, connector C415, pin 69, circuit 31S-FA11 (BK/YE), wiring harness side and the A/C WOT relay, socket C1011, pin 2, wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
CHECK the PCM and RENEW if necessary. CHECK the operation of the system.
No
LOCATE and REPAIR the break in the circuit between the PCM and the A/C WOT relay using the Wiring Diagrams. CHECK the operation of the system.
D24: CHECK FOR OPEN CIRCUIT BETWEEN THE DUAL PRESSURE SWITCH AND THE HEATER CONTROL MODULE
1
Ignition switch in position 0.
2
Disconnect connector C380 from heater control module.

3
Measure the resistance between the dual pressure switch, connector C882, pin 1, circuit 15S-FA38 (GN/RD), wiring harness side and the heater control module, connector C380, pin 9, circuit 15S-FA38 (GN/RD), wiring harness side.

Is a resistance of less than 2 Ohms registered?
Yes
GO to D25.
No
LOCATE and REPAIR the break in circuit in 15S-FA38 (GN/RD) between the dual pressure switch and the heater control module using the Wiring Diagrams. CHECK the operation of the system.
D25: CHECK THE GROUND CONNECTION OF THE HEATER CONTROL MODULE

1
Measure the resistance between the heater control module, connector C380, pin 12, circuit 91-FA13 (BK/OG), wiring harness side and ground.

Is a resistance of less than 2 Ohms registered?
Yes
GO to D26.
No
LOCATE and REPAIR the break in the circuit between the heater control module and ground connection G41 using the Wiring Diagrams. CHECK the operation of the system.
D26: CHECK THE VOLTAGE AT THE HEATER CONTROL MODULE

1
Measure the voltage between the heater control module, connector C380, pin 8, circuit 29-FA13 (OG), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to D27.
No
LOCATE and REPAIR the break in the circuit between the heater control module and fuse F36 using the Wiring Diagrams. CHECK the operation of the system.
D27: CHECK THE VOLTAGE AT THE HEATER CONTROL MODULE
1
Ignition switch in position II.

2
Measure the voltage between the heater control module, connector C380, pin 10, circuit 15-FA13 (GN/RD), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to D28.
No
LOCATE and REPAIR the break in the circuit between the heater control module and fuse F45 using the Wiring Diagrams. CHECK the operation of the system.
D28: CHECK THE CONTROL VOLTAGE AT THE HEATER CONTROL MODULE
1
Set the heater blower switch to "Off".

2
Measure the voltage between the heater control module, connector C380, pin 6, circuit 31S-FA26 (BK/RD), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to D29.
No
LOCATE and REPAIR the break in circuit 31S-FA26 (BK/RD) between the heater control module and the heater blower switch using the Wiring Diagrams. CHECK the operation of the system.
D29: CHECK THE VOLTAGE AT THE HEATER CONTROL MODULE
1
Ignition switch in position III.

2
Measure the voltage between the heater control module, connector C380, pin 11, circuit 64-HB6A (BU), wiring harness side and ground.

Does the meter display battery voltage?
Yes
CHECK the heater control module and RENEW as necessary. CHECK the operation of the system.
No
LOCATE and REPAIR the break in the circuit between the heater control module and the engine run relay using the Wiring Diagrams. CHECK the operation of the system.

General Procedures > < 412-00 Climate Control System - General Information|Specifications