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Diagnosis and Testing|Removal and Installation > < Fuel Fired Booster Heater

Focus 2004.75 (07.2004-)

Auxiliary Heating - Electric Booster Heater Focus 2004.75 (07/2004-)
Diagnosis and Testing

Special Tool(s)

Terminal probe kit

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

Description of operation

NOTE:
NOTE:The generic electronic module (GEM) is integrated in the central junction box (CJB).

The electric booster heater consists of three individual heating elements, which are incorporated into a single housing.

To switch the electric booster heater on, the temperature in the passenger compartment needs to be set to HI or the heater controls need to be set to their highest setting. An "electric booster heater ON" request signal is then sent by the electronic automatic temperature control module via the CAN bus to the Generic Electronic Module (GEM). On vehicles with a conventional air conditioning, the signal "electric booster heater ON" is sent via a conventional wire connection.

The booster heater is controlled by the Generic Electronic Module (GEM) in accordance with the following factors:

- The electric booster heater is only activated at ambient temperatures below 10°C.

- The electric booster heater is switched off when the coolant temperature exceeds 70°C. The heater is not reactivated until the coolant temperature has fallen below 60°C.

- Whether or not the electric booster heater is activated also depends on the available alternator capacity.

NOTE:
NOTE:The electric booster heater is only activated if all conditions are fulfilled.

Control

The electric booster heater electronics activate three output stages as a function of a pulse width modulated signal (PWM) generated by the GEM. The output stages switch the three heating elements of the electric booster heater ON or OFF individually, whereby the heating periods of the individual elements can overlap. Due to the variable switch-on duration, continuously variable temperature control is possible. The overall heating power of the three heating elements is linearly proportional to the PWM signal. If the PWM signal is below 10% or above 95%, the electric booster heater is not activated.

Inspection and Checking

  1. VERIFY customer concern.
  1. Visually CHECK for any obvious mechanical or electrical damage.
NOTE:
NOTE:Ensure correct locking of wiring harness connector.

Visual Inspection

Electrical
  • 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, the GEM and the charging system 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.
  1. Following checking or elimination of the fault and after completion of operations, the fault memories of all vehicle modules must be READ OUT and any stored faults must be DELETED. READ OUT all fault memories again following a road test.

Symptom Chart

Symptom Chart

Symptom Possible Sources Action
Electric booster heater inoperative
*
Fuse(s)
*
Circuit(s)
*
Electric booster heater
*
Generic electronic module (GEM)
*
Air conditioning control assembly
*
Electronic automatic temperature control module
*
GO to Pinpoint Test A.

System Test

PINPOINT TEST A : ELECTRIC BOOSTER HEATER INOPERATIVE
NOTE:
NOTE:Check whether all above-mentioned activation conditions have been fulfilled.
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
A1: CHECK THE REQUEST SIGNAL "ELECTRIC BOOSTER HEATER ON" WITH WDS
NOTE:
NOTE:The generic electronic module (GEM) is integrated into the central junction box (CJB).
1
Ignition switch in position 0.
2
Connect the diagnostic tool.
3
Select the GEM with the diagnostic unit.
4
Set the interior temperature to HI or the heater controls to their highest setting.
5
Check whether an "electric booster heater ON" request signal is displayed in the data logger.

Is an "electric booster heater ON" request signal displayed in the data logger of the GEM?
Yes
GO to A4.
No
- Vehicles with electronic automatic temperature control:CHECK the EATC module with WDS. RENEW the EATC module as required. CHECK the operation of the system.
- Vehicles without electronic automatic temperature control:GO to A2.
A2: CHECK THE REQUEST SIGNAL "ELECTRIC BOOSTER HEATER ON" AT THE GEM
1
Ignition switch in position 0.
2
Disconnect Connector C103 from GEM.
3
Ignition switch in position II.
4
Set the heater controls on the A/C control assembly to the highest setting.
5
Measure the voltage between the GEM, connector C103, pin 14, circuit 8-FC10 (WH/VT), wiring harness side and ground.

Does the meter display battery voltage?
Yes
CHECK the GEM using WDS. If necessary RENEW the GEM. CHECK the operation of the system.
No
GO to A3.
A3: TEST THE CIRCUIT BETWEEN THE GEM AND THE A/C CONTROL ASSEMBLY FOR OPEN CIRCUIT
1
Ignition switch in position 0.
2
Disconnect Connector C378 from A/C control assembly.
3
Measure the resistance between the GEM, connector C103, pin 14, circuit 8-FC10 (WH/VT), wiring harness side and the A/C control assembly, connector C378, pin 5, circuit 8-FC10 (WH/VT), wiring harness side.

Is a resistance of less than 2 Ohm registered?
Yes
RENEW the A/C control assembly. CHECK the operation of the system.
No
LOCATE and REPAIR the break in circuit 8-FC10 (WH/VT) between the GEM and the A/C control assembly using the Wiring Diagrams. CHECK the operation of the system.
A4: CHECK FUSE F5
1
Ignition switch in position 0.
2
CHECK Fuse F5 (BJB).

Is the fuse OK?
Yes
GO to A5.
No
RENEW fuse F5 (80 A). CHECK the operation of the system. If the fuse blows again, LOCATE and REPAIR the short using the Wiring Diagrams.
A5: CHECK THE VOLTAGE AT FUSE F5
1
Connect Fuse F5 (BJB).
2
Measure the voltage between fuse F5 (80 A) and ground.

Does the meter display battery voltage?
Yes
GO to A7.
No
REPAIR the voltage supply to fuse F5. CHECK the operation of the system.
A6: DETERMINE THE EQUIPMENT LEVEL OF THE CENTRAL JUNCTION BOX (CJB).
1
Unfasten the CJB and fold it down.

Is the location for connector C100 on the top of the CJB?
Yes
GO to A7.
No
GO to A9.
A7: CHECK FUSE F100
1
CHECK Fuse F100 (CJB).

Is the fuse OK?
Yes
GO to A8.
No
RENEW fuse F100 (10 A) (CJB). CHECK the operation of the system. If the fuse blows again, LOCATE and REPAIR the short using the Wiring Diagrams.
A8: CHECK THE VOLTAGE AT FUSE F100
1
Connect Fuse F100 (CJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F100 (10 A) and ground.

Does the meter display battery voltage?
Yes
GO to A11.
No
REPAIR the voltage supply of fuse F100 CHECK the operation of the system.
A9: CHECK FUSE F70
1
CHECK Fuse F70 (CJB).

Is the fuse OK?
Yes
GO to A10.
No
RENEW fuse F70 (10 A). CHECK the operation of the system. If the fuse blows again, LOCATE and REPAIR the short using the Wiring Diagrams.
A10: CHECK THE VOLTAGE AT FUSE F70
1
Connect Fuse F70 (CJB).
2
Ignition switch in position II.
3
Measure the voltage between fuse F70 (10 A) and ground.

Does the meter display battery voltage?
Yes
GO to A11.
No
REPAIR the voltage supply to fuse F70. CHECK the operation of the system.
A11: CHECK THE VOLTAGE AT THE ELECTRIC BOOSTER HEATER
1
Ignition switch in position 0.
2
Disconnect Connector C861 from electric booster heater.

3
Measure the voltage between the electric booster heater, connector C861, pin 1, circuit 30-FC9 (RD), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to A13.
No
LOCATE and REPAIR the break in circuit 30-FC9 (RD) between the electric booster heater and fuse F5 using the Wiring Diagrams. CHECK the operation of the system.
A12: CHECK THE ELECTRIC BOOSTER HEATER GROUND CONNECTION
1
Disconnect Connector C878 from electric booster heater.

2
Measure the resistance between the electric booster heater, connector C878, pin 1, circuit 31-FC9 (BK) (RHD vehicles: circuit 31-FC9A (BK)), wiring harness side and ground.

Is a resistance of 0.0 - 0.1 Ohm registered?
Yes
GO to A13.
No
LOCATE and RECTIFY the open circuit in circuit 31-FC9 (BK) between the electric booster heater and ground connection G58 with the aid of the Wiring Diagrams. CHECK the operation of the system.
A13: CHECK CONTROL VOLTAGE AT ELECTRIC BOOSTER HEATER
1
Disconnect Connector C851 from electric booster heater.
2
Ignition switch in position II.

3
Measure the voltage between the electric booster heater, connector C851, pin 1, circuit 15-FC9 (GN/OG), wiring harness side and ground.

Does the meter display battery voltage?
Yes
GO to A15.
No
GO to A14.
A14: CHECK FOR OPEN CIRCUIT BETWEEN THE ELECTRIC BOOSTER HEATER AND THE CJB - TERMINAL 15
1
Ignition switch in position 0.
2
Disconnect Connector C102 from CJB.

3
Measure the resistance between the electric booster heater, connector C851, pin 1, circuit 15-FC9 (GN/OG), wiring harness side and the CJB, connector C102, pin 5, circuit 15-DA4 (GN/BK), wiring harness side.

Is a resistance of less than 2 Ohm registered?
Yes
CHECK the CJB and RENEW as necessary. CHECK the operation of the system.
No
LOCATE and REPAIR the break in the circuit between the electric booster heater and the CJB using the Wiring Diagrams. CHECK the operation of the system.
A15: CHECK FOR OPEN CIRCUIT BETWEEN THE ELECTRIC BOOSTER HEATER AND THE CJB - PWM SIGNAL
1
Ignition switch in position 0.
2
Disconnect Connector C103 from CJB.

3
Measure the resistance between the electric booster heater, connector C851, pin 2, circuit 8-FC9 (WH/BK), wiring harness side and the CJB, connector C103, pin 9, circuit 8-FC9 (WH/BK), wiring harness side.

Is a resistance of less than 2 Ohm registered?
Yes
GO to A16.
No
LOCATE and REPAIR the break in circuit 8-FC9 (WH/BK) between the electric booster heater and the CJB using the Wiring Diagrams. CHECK the operation of the system.
A16: CHECK THE CIRCUIT BETWEEN THE ELECTRIC BOOSTER HEATER AND THE CJB FOR A SHORT TO VOLTAGE
NOTE:
NOTE:For the following measurement the interior temperature must be set to "LO" or the heating controls must be set to "COLD".
1
Connect Connector C103 to CJB.
2
Ignition switch in position II.

3
Measure the voltage between the electric booster heater, connector C851, pin 2, circuit 8-FC9 (WH/BK), wiring harness side and ground.

Is a voltage measured?
Yes
LOCATE and REPAIR the short to voltage in circuit 8-FC9 (WH/BK) between the electric booster heater and the CJB using the Wiring Diagrams. CHECK the operation of the system.
No
GO to A17.
A17: CHECK THE CIRCUIT BETWEEN THE ELECTRIC BOOSTER HEATER AND THE CJB FOR A SHORT TO GROUND
1
Ignition switch in position 0.

2
Measure the resistance between the electric booster heater, connector C851, pin 2, circuit 8-FC9 (WH/BK), wiring harness side and ground.

Is a resistance of more than 10,000 Ohms measured?
Yes
RENEW the electric booster heater. CHECK the operation of the system. If the electric booster heater is still inoperative, CHECK and if necessary RENEW the CJB.
No
LOCATE and REPAIR the short to ground in circuit 8-FC9 (WH/BK) between the electric booster heater and the CJB using the Wiring Diagrams. CHECK the operation of the system.

Diagnosis and Testing|Removal and Installation > < Fuel Fired Booster Heater