Pinpoint tests of microclimate control (cars up to 07.2001) (Focus 1)

A1: CHECKING THE OPERATION OF THE A/C COMPRESSOR CLUTCH

1Enter the START position.

2Turn on the air conditioning system.

3Turn on the heater fan.

4Check the operation of the air conditioning compressor clutch.

• Is the air conditioning compressor clutch working?

→ Yes

CHECK the refrigerant circuit and the amount of refrigerant and ADJUST if necessary. CHECK the correct operation of the system.

→ No

Go to A2

A2: READING FDS/WDS FAULT CODES

1Enter the OFF position.

2Run the Engine Management System Diagnostic Program to retrieve trouble codes using FDS/WDS.

• Is there a fault code related to the air conditioning system?

→ Yes

PERFORM the necessary troubleshooting steps as directed by the FDS/WDS. CHECK that the system is operating correctly.

→ No

Go to A3

A3: CHECKING FUSE F58

1CHECK Fuse F58 (CJB).

• Is the fuse good?

→ Yes

Go to A4

→ No

REPLACE fuse F58 (7.5A). If the fuse blows again after turning on the A/C system, CHECK the A/C compressor clutch diode and REPLACE it if necessary. If the diode is OK, LOCATE and REPAIR the short to ground using the wiring diagrams. CHECK the system for proper operation.

A4: CHECKING THE VOLTAGE AT FUSE F58

1Connect Fuse F58 (CJB).

2Enter the ON position.

3Check the voltage in the electrical circuit between fuse F58 (7.5 A) and ground.

• Is battery voltage registered?

→ Yes

Go to A5

→ No

RESTORE power to fuse F58 using the wiring diagrams. CHECK that the system is operating correctly.

A5: CHECKING FUSE F36

1Enter the OFF position.

2CHECK Fuse F36 (CJB).

• Is the fuse good?

→ Yes

Go to A6

→ No

REPLACE fuse F36 (7.5A). If the fuse blows again, LOCATE and REPAIR the short to ground using the wiring diagrams. CHECK the system for proper operation.

A6: CHECKING THE VOLTAGE AT FUSE F36

1Connect Fuse F36 (CJB).

2Check the voltage in the electrical circuit between fuse F36 (7.5 A) and ground.

• Is battery voltage registered?

→ Yes

Cars manufactured before 05.99: Go to A7

Cars manufactured since 05.99: Go to A10

→ No

RESTORE power to fuse F36 using the wiring diagrams. CHECK that the system is operating correctly.

A7: CHECKING THE VOLTAGE AT THE A/C WIDE OPEN THROTTLE (WOT) CUT-OFF RELAY

1Disconnect C1011 A/C WOT relay.

2Enter the ON position.

3Measure the voltage between pin 3 of the A/C WOT relay connector C1011, wiring harness side, and ground.

• Is battery voltage registered?

→ Yes

Go to A11

→ No

Go to A8

A8: CHECKING THE SUPPLY VOLTAGE IN THE DUAL PRESSURE SWITCH

1Enter the OFF position.

2Disconnect C882 dual pressure switch.

3Enter the ON position.

4Measure the voltage between pin 2 of dual pressure switch connector C882, circuit 15-FA38 (green/red), wiring harness side, and ground.

• Is battery voltage registered?

→ Yes

Go to A9

→ No

LOCATE and REPAIR the open circuit between fuse F58 and dual pressure switch using the wiring diagrams. CHECK the system for proper operation.

A9: CHECKING THE DUAL PRESSURE SWITCH

1Enter the OFF position.

2Measure the resistance between pins 2 and 4 of the C882 dual pressure switch connector, element side.

• Is the resistance registered less than 2 ohms?

→ Yes

LOCATE and REPAIR the open in the electrical circuit between the dual pressure switch and the A/C WOT switch using the wiring diagrams. CHECK the system for proper operation.

→ No

CHECK the air conditioning system pressure and REPAIR as necessary. If the system pressure is correct, REPLACE the dual pressure switch. CHECK the system for proper operation.

A10: CHECKING THE VOLTAGE AT THE A/C WIDE OPEN THROTTLE (WOT) CUT-OFF RELAY

1Disconnect C1011 A/C WOT relay.

2Enter the ON position.

3Measure the voltage between pin 3 of the A/C WOT relay connector C1011, wiring harness side, and ground.

• Is battery voltage registered?

→ Yes

Go to A11

→ No

LOCATE and REPAIR the open in the electrical circuit between the A/C WOT relay and fuse F58 using the wiring diagrams. CHECK the system for proper operation.

A11: CHECKING SUPPLY VOLTAGE AT A/C WOT RELAY

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

• Is battery voltage registered?

→ Yes

Go to A12

→ No

RESTORE power to the A/C WOT relay using the wiring diagrams. CHECK for proper system operation.

A12: CHECKING A/C COMPRESSOR CLUTCH CIRCUIT

1Enter the OFF position.

2Install a 7.5A fused jumper cable between pins 3 and 5 of the A/C WOT relay connector C1011, on the wiring harness side.

3Enter the ON position.

4Check the operation of the air conditioning compressor clutch.

• Is the air conditioning compressor clutch working?

→ Yes

Go to A15

→ No

Go to A13

A13: CHECKING A/C COMPRESSOR CLUTCH SUPPLY VOLTAGE

1Enter the OFF position.

2Disconnect C952 A/C compressor clutch.

3Install a 7.5A fused jumper cable between pins 3 and 5 of the A/C WOT relay connector C1011, on the wiring harness side.

4Enter the ON position.

5Measure the voltage between A/C compressor clutch connector C952 pin 1, circuit 15S-FA6 (GN/YE), harness side and ground.

• Is battery voltage registered?

→ Yes

Go to A14

→ No

LOCATE and REPAIR the open in the electrical circuit between the A/C WOT relay and the A/C compressor clutch using the wiring diagrams. CHECK the system for proper operation.

A14: CHECKING THE A/C COMPRESSOR CLUTCH GROUND CIRCUIT

1Enter the OFF position.

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

• Is the resistance registered less than 2 ohms?

→ Yes

REPLACE the air conditioning compressor clutch. CHECK the system for proper operation.

→ No

LOCATE and REPAIR the open in the electrical circuit between the A/C compressor clutch and ground point G56 using the wiring diagrams. CHECK for proper system operation.

A15: CHECKING THE A/C WIDE OPEN THROTTLE (WOT) CUT-OFF RELAY

1Check the A/C WOT relay by following the component tests described at the end of this section.

• Is the A/C WOT relay OK?

→ Yes

Go to A16

→ No

REPLACE the A/C WOT relay. CHECK the system for proper operation.

A16: CHECKING POWER VOLTAGE AT A/C COMPRESSOR SWITCH

1Enter the OFF position.

2Disconnect C692 air conditioning compressor switch.

3Enter the ON position.

4Turn on the air conditioning system.

5Turn on the heater fan.

6Measure the voltage between pin 4 of the air conditioning compressor switch connector C692, circuit 15S-FA17 (Green/Orange), wiring harness side and ground.

• Is battery voltage registered?

→ Yes

Go to A17

→ No

Go to A24

A17: CHECKING A/C COMPRESSOR SWITCH

1Enter the OFF position.

2Measure the resistance between pins 4 and 1 of connector C692 of the air conditioning compressor cycling switch, on the component side.

• Is the resistance registered less than 2 ohms?

→ Yes

Cars manufactured before 05.99 with EEC V (60-pin): Go to A20

Cars manufactured before 05.99 with EEC V (104-pin): Go to A22

Cars manufactured since 05.99 Go to A18

→ No

CHECK the refrigerant charge and ADJUST if necessary. If the refrigerant charge is correct, REPLACE the A/C compressor cycling switch. CHECK the system for proper operation.

A18: CHECKING THE SUPPLY VOLTAGE IN THE DUAL PRESSURE SWITCH

1Connect C692 to the air conditioning compressor switch.

2Disconnect Dual Pressure Switch C882.

3Enter the ON position.

4Turn on the air conditioning system.

5Turn on the heater fan.

6Measure the voltage between pin 2 of dual pressure switch connector C882, circuit 15S-FA38 (green/red), wiring harness side, and ground.

• Is battery voltage registered?

→ Yes

Go to A19

→ No

LOCATE and REPAIR the open in the C circuit between the A/C compressor switch and the dual pressure switch using the wiring diagrams. CHECK for proper system operation.

A19: CHECKING THE DUAL PRESSURE SWITCH

1Enter the OFF position.

2Measure the resistance between pins 2 and 4 of the C882 dual pressure switch connector, element side.

• Is the resistance registered less than 2 ohms?

→ Yes

Vehicles with EEC V (60-pin): Go to A20

Vehicles with EEC V (104-pin): Go to A22

→ No

CHECK the air conditioning system pressure and REPAIR as necessary. If the system pressure is correct, REPLACE the dual pressure switch. CHECK the system for proper operation.

A20: CHECKING VOLTAGE IN PCM

1Connect C882 dual pressure switch.

2Disconnect C416 PCM.

3Enter the ON position.

4Turn on the air conditioning system.

5Turn on the heater fan.

6Measure the voltage between PCM connector C416 pin 10, circuit 15S-RE18 (GN/YE), (vehicles built since 05/99): circuit 15S-RE8 (GN/YE), wiring harness side and ground.

• Is battery voltage registered?

→ Yes

Go to A21

→ No

LOCATE and REPAIR the open in the 15S-RE18 (green/yellow) or 15S-RE8 (green/yellow) circuit using the wiring diagrams. CHECK that the system is operating correctly.

A21: CHECKING VOLTAGE IN PCM

1Enter the OFF position.

2Connect C1011 to A/C WOT relay.

3Enter the ON position.

4Measure the voltage between PCM connector C416 pin 54, circuit 31S-FA11 (BK/YE), wiring harness side and ground.

• Is battery voltage registered?

→ Yes

CHECK the PCM and REPLACE it if necessary. CHECK the system for proper operation.

→ No

LOCATE and REPAIR the open in the circuit between the A/C WOT relay and the PCM using the wiring diagrams. CHECK the system for proper operation.

A22: CHECKING VOLTAGE IN PCM

1Connect C882 dual pressure switch.

2Disconnect C415 PCM.

3Enter the ON position.

4Turn on the air conditioning system.

5Turn on the heater fan.

6Measure the voltage between PCM connector C415 pin 41, circuit 15S-RE18 (GN/YE), (vehicles built since 05/99): circuit 15S-RE8 (GN/YE), wiring harness side and ground.

• Is battery voltage registered?

→ Yes

Go to A23

→ No

LOCATE and REPAIR the open in the 15S-RE18 (green/yellow) or 15S-RE8 (green/yellow) circuit using the wiring diagrams. CHECK that the system is operating correctly.

A23: CHECKING VOLTAGE IN PCM

1Enter the OFF position.

2Connect C1011 to A/C WOT relay.

3Enter the ON position.

4Measure the voltage between PCM connector C415 pin 69, circuit 31S-FA11 (BK/YE), wiring harness side and ground.

• Is battery voltage registered?

→ Yes

CHECK the PCM and REPLACE it if necessary. CHECK the system is operating correctly.

→ No

LOCATE and REPAIR the open in the circuit between the A/C WOT relay and the PCM using the wiring diagrams. CHECK the system for proper operation.

A24: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE A/C COMPRESSOR SWITCH

1Enter the OFF position.

2Disconnect the C380 Heater Control Module.

3Measure the resistance between pin 9 of the heater control module connector C380, circuit 15S-FA17 (GN/OG), wire harness side and pin 4 of the A/C compressor switch connector C692, circuit 15S-FA17 (GN/OG), wire harness side.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to A25

→ No

LOCATE and REPAIR the open in the 15S-FA17 (Green/Orange) circuit between the Heater Control Module and the A/C Compressor Switch using the Wiring Diagrams. CHECK for proper system operation.

A25: CHECKING VOLTAGE IN THE HEATER CONTROL MODULE

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

• Is battery voltage registered?

→ Yes

Go to A26

→ No

LOCATE and REPAIR the open in the electrical circuit between fuse F36 and the heater control module using the wiring diagrams. CHECK the system for proper operation.

A26: CHECKING VOLTAGE IN THE HEATER CONTROL MODULE

1Enter the ON position.

2Measure the voltage between pin 10 of the heater control module connector C380 and ground.

• Is battery voltage registered?

→ Yes

Go to A27

→ No

LOCATE and REPAIR the open in the electrical circuit between the heater control module and fuse F58 using the wiring diagrams. CHECK the system for proper operation.

A27: CHECKING VOLTAGE IN THE HEATER CONTROL MODULE

1Enter the START position.

2Measure the voltage between pin 11 of the heater control module connector C380, wiring harness side, and ground.

• Is battery voltage registered?

→ Yes

Go to A28

→ No

LOCATE and REPAIR the open in the electrical circuit between the heater control module and the engine run relay using the wiring diagrams. CHECK the system for proper operation.

A28: CHECKING THE HEATER CONTROL MODULE GROUND CIRCUIT

1Enter the OFF position.

2Measure the resistance between pin 12 of the heater control module connector C380, circuit 91-FA13 (black/orange), wiring harness side, and ground.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to A29

→ No

LOCATE and REPAIR the open in the electrical circuit between the heater control module and ground point G41 using the wiring diagrams. CHECK for proper system operation.

A29: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE HEATER BLOWER SWITCH

1Set the heater fan switch to low speed.

2Measure the resistance between pin 6 of the heater control module connector C380, circuit 31S-FA26 (black/red), wiring harness side, and ground.

• Is the resistance registered less than 2 ohms?

→ Yes

CHECK and if necessary REPLACE the heater control module. CHECK the system is operating correctly.

→ No

LOCATE and REPAIR the open in circuit 31S-FA26 (BK/RD) between the Heater Control Module and the Heater Blower Switch using the Wiring Diagrams. CHECK for proper system operation.

B1: DETERMINING THE CONDITIONS UNDER WHICH A FAILURE OCCURRES

1Enter the ON position.

2Cycle the heater fan switch through all three positions.

• The heater fan motor does not operate in all three switch positions?

→ Yes

Go to B2

→ No

Go to B10

B2: CHECKING FUSE F64

1Enter the OFF position.

2CHECK Fuse F64 (BJB).

• Is the fuse good?

→ Yes

Go to B3

→ No

REPLACE fuse F64 (30A). CHECK the system for proper operation. If the fuse blows again, LOCATE and REPAIR the short to ground using the wiring diagrams.

B3: CHECKING THE VOLTAGE IN FUSE F64

1Connect Fuse F64 (BJB).

2Enter the ON position.

3Check the voltage in the electrical circuit between fuse F64 (30 A) and ground.

• Is battery voltage registered?

→ Yes

Go to B4

→ No

RESTORE power to fuse F64 using the wiring diagrams. CHECK that the system is operating correctly.

B4: CHECKING THE VOLTAGE IN THE HEATER FAN MOTOR

1Enter the OFF position.

2Disconnect C789 heater blower motor.

3Enter the ON position.

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

• Is battery voltage registered?

→ Yes

Go to B5

→ No

LOCATE and REPAIR the open in the electrical circuit between the heater blower motor and fuse F64 using the wiring diagrams. CHECK the correct operation of the system.

B5: CHECKING THE ELECTRICAL GROUND CIRCUIT OF THE HEATER ELECTRIC FAN

1Enter the OFF position.

2Set the heater fan switch to "maximum".

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

• Is the resistance registered less than 2 ohms?

→ Yes

REPLACE the heater blower. CHECK the system for proper operation.

→ No

Cars manufactured before 01.00: Go to B6

Cars manufactured since 01.00: Go to B8

B6: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER FAN MOTOR AND THE HEATER FAN SWITCH

1Disconnect C469 heater fan switch.

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

• Is the resistance registered less than 2 ohms?

→ Yes

Go to B7

→ No

LOCATE and REPAIR the open in the 31S-FA18 (black/red) circuit between the heater blower motor and solder joint S24 using the wiring diagrams. CHECK the system for proper operation.

B7: CHECKING THE HEATER FAN SWITCH GROUND CIRCUIT

1Measure the resistance between pin 6 of the heater blower switch connector C469, circuit 31-FA25 (black), wiring harness side and ground.

• Is the resistance registered less than 2 ohms?

→ Yes

REPLACE the heater fan switch. CHECK the system for proper operation.

→ No

LOCATE and REPAIR the open in the electrical circuit between the heater blower switch and ground point G14 using the wiring diagrams. CHECK the system for proper operation.

B8: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER FAN MOTOR AND THE HEATER FAN SWITCH

1Disconnect C469 heater fan switch.

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

• Is the resistance registered less than 2 ohms?

→ Yes

Go to B9

→ No

LOCATE and REPAIR the open in the 31S-FA18 (black/red) circuit between the heater blower motor and solder joint S24 using the wiring diagrams. CHECK the system for proper operation.

B9: CHECKING THE HEATER FAN SWITCH GROUND CIRCUIT

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

• Is the resistance registered less than 2 ohms?

→ Yes

REPLACE the heater fan switch. CHECK the system for proper operation.

→ No

LOCATE and REPAIR the open in the electrical circuit between the heater blower switch and ground point G14 using the wiring diagrams. CHECK the system for proper operation.

B10: DETERMINING THE CONDITIONS UNDER WHICH A FAULT OCCURRS

1Set the heater fan switch to "maximum".

• Heater fan motor not working?

→ Yes

Cars manufactured before 01.00: Go to B11

Cars manufactured since 01.00: Go to B12

→ No

Cars manufactured before 01.00: Go to B13

Cars manufactured since 01.00: Go to B18

B11: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER FAN MOTOR AND THE HEATER FAN SWITCH

1Enter the OFF position.

2Disconnect C469 heater fan switch.

3Disconnect C789 heater blower motor.

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

• Is the resistance registered less than 2 ohms?

→ Yes

REPLACE the heater fan switch. CHECK the system for proper operation.

→ No

LOCATE and REPAIR the open in circuit 31S-FA33 (Black/Orange) between the heater blower switch and solder joint S24 using the wiring diagrams. CHECK for proper system operation.

B12: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER FAN MOTOR AND THE HEATER FAN SWITCH

1Enter the OFF position.

2Disconnect C469 heater fan switch.

3Disconnect C789 heater blower motor.

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

• Is the resistance registered less than 2 ohms?

→ Yes

REPLACE the heater fan switch. CHECK the system for proper operation.

→ No

LOCATE and REPAIR the open in circuit 31S-FA33 (Black/Orange) between the heater blower switch and solder joint S24 using the wiring diagrams. CHECK for proper system operation.

B13: CHECKING THE HEATER FAN SWITCH

1Enter the OFF position.

2Disconnect C469 heater fan switch.

3Enter the ON position.

4Measure the voltage between pin 1 of the heater blower switch connector C469, circuit 31S-FA32 (BLK/BU), wiring harness side, and ground.

5Measure the voltage between pin 2 of the heater blower switch connector C469, circuit 31S-FA31 (BK/YE), wiring harness side and ground.

6Measure the voltage between pin 3 of the heater blower switch connector C469, circuit 31S-FA30 (BK/WH), wiring harness side and ground.

• Is battery voltage registered during all measurements?

→ Yes

REPLACE the heater fan switch. CHECK the system for proper operation.

→ No

Go to B14

B14: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER FAN MOTOR AND THE HEATER FAN VARIABLE RESISTOR.

1Enter the OFF position.

2Disconnect C470 heater blower variable resistor.

3Enter the ON position.

4Measure the voltage between pin 1 of the C470 connector of the variable resistor of the heater electric fan, electrical circuit 31S-FA1 (black/blue), on the wiring harness side, and ground.

• Is battery voltage registered?

→ Yes

Go to B15

→ No

LOCATE and REPAIR the open in the 31S-FA1 (BLK/BLUE) circuit between the heater blower variable resistor and solder joint S24 using the Wiring Diagrams. CHECK for proper system operation.

B15: CHECK CIRCUIT BETWEEN HEATER BLOWER VARIABLE RESISTOR AND HEATER BLOWER SWITCH

1Enter the OFF position.

2Measure the resistance between pin 4 of connector C470 of the heater blower motor variable resistor, circuit 31S-FA32 (BLK/BU), wiring harness side and pin 1 of connector C469 of the heater blower switch, circuit 31S-FA32 (BLK/BU), wiring harness side.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to B16

→ No

LOCATE and REPAIR the open in the 31S-FA32 (BLK/BLUE) circuit between the heater blower motor variable resistor and the heater blower switch using the wiring diagrams. CHECK for proper system operation.

B16: CHECK CIRCUIT BETWEEN HEATER FAN VARIABLE RESISTOR AND HEATER FAN SWITCH

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

• Is the resistance registered less than 2 ohms?

→ Yes

Go to B17

→ No

LOCATE and REPAIR the open in the 31S-FA31 (BK/YEL) circuit between the heater blower motor variable resistor and the heater blower switch using the wiring diagrams. CHECK for proper system operation.

B17: CHECK CIRCUIT BETWEEN HEATER BLOWER VARIABLE RESISTOR AND HEATER BLOWER SWITCH

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

• Is the resistance registered less than 2 ohms?

→ Yes

REPLACE the heater blower motor variable resistor. CHECK the system for proper operation.

→ No

LOCATE and REPAIR the open in the 31S-FA30 (BK/YEL) circuit between the heater blower motor variable resistor and the heater blower switch using the wiring diagrams. CHECK for proper system operation.

B18: CHECKING THE HEATER FAN SWITCH

1Enter the OFF position.

2Disconnect C469 heater fan switch.

3Enter the ON position.

4Measure the voltage between pin 5 of the heater blower switch connector C469, circuit 31S-FA32 (BLK/BU), wiring harness side, and ground.

5Measure the voltage between pin 3 of the heater blower switch connector C469, circuit 31S-FA31 (BK/YE), wiring harness side and ground.

6Measure the voltage between pin 1 of the heater blower switch connector C469, circuit 31S-FA30 (BK/WH), wiring harness side and ground.

• Is battery voltage registered during all measurements?

→ Yes

REPLACE the heater fan switch. CHECK the system for proper operation.

→ No

Go to B19

B19: CHECK THE ELECTRICAL CIRCUIT BETWEEN THE HEATER FAN MOTOR AND THE HEATER FAN VARIABLE RESISTOR.

1Enter the OFF position.

2Disconnect C470 heater blower variable resistor.

3Enter the ON position.

4Measure the voltage between pin 1 of connector C470 of the heater blower motor variable resistor, circuit 31S-FA1 (black/blue) (from 08/2000 circuit 31S-FA33 (black/orange)), wiring harness side, and ground.

• Is battery voltage registered?

→ Yes

Go to B20

→ No

LOCATE and REPAIR the open in the electrical circuit between solder joint S24 and the heater blower variable resistor using the wiring diagrams. CHECK the system for proper operation.

B20: CHECK CIRCUIT BETWEEN HEATER BLOWER VARIABLE RESISTOR AND HEATER BLOWER SWITCH

1Enter the OFF position.

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

• Is the resistance registered less than 2 ohms?

→ Yes

Go to B21

→ No

LOCATE and REPAIR the open in the 31S-FA32 (BLK/BLUE) circuit between the heater blower motor variable resistor and the heater blower switch using the wiring diagrams. CHECK for proper system operation.

B21: CHECK CIRCUIT BETWEEN HEATER FAN VARIABLE RESISTOR AND HEATER FAN SWITCH

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

• Is the resistance registered less than 2 ohms?

→ Yes

Go to B22

→ No

LOCATE and REPAIR the open in the 31S-FA31 (BK/YEL) circuit between the heater blower motor variable resistor and the heater blower switch using the wiring diagrams. CHECK for proper system operation.

B22: CHECK CIRCUIT BETWEEN HEATER FAN VARIABLE RESISTOR AND HEATER FAN SWITCH

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

• Is the resistance registered less than 2 ohms?

→ Yes

REPLACE the heater blower motor variable resistor. CHECK the system for proper operation.

→ No

LOCATE and REPAIR the open in the 31S-FA30 (BK/YEL) circuit between the heater blower motor variable resistor and the heater blower motor switch using the wiring diagrams. CHECK for proper system operation.

C1: CHECKING THE HEATER FAN SWITCH

1Enter the OFF position.

2Disconnect C469 heater fan switch.

3Enter the ON position.

4Check the operation of the heater electric fan.

• Does the heater fan motor run continuously?

→ Yes

Go to C2

→ No

REPLACE the heater fan switch. CHECK the system for proper operation.

C2: CHECK THE CIRCUIT TO THE HEATER FAN VARIABLE RESISTOR

1Enter the OFF position.

2Disconnect C470 heater blower variable resistor.

3Enter the ON position.

4Check the operation of the heater electric fan.

• Does the heater fan motor run continuously?

→ Yes

CHECK all electrical circuits connected to solder point S24 for short to ground using the wiring diagrams and REPAIR. CHECK proper system operation.

→ No

CHECK all electrical circuits between the heater blower variable resistor and the heater blower switch for short to ground using the wiring diagrams and REPAIR. CHECK proper system operation.

D1: DETERMINING THE MODEL VARIANT

1Determine the model option.

• Was the car manufactured before 05.99?

→ Yes

Go to D2

→ No

Go to D8

D2: CHECKING THE GROUNDING CIRCUIT OF THE AIR RECIRCULATION FLAP POSITIONING MOTOR

1Enter the OFF position.

2Disconnect C375 Air Recirculation Damper Positioning Motor.

3Measure the resistance between pin 4 of the air recirculation flap positioning motor connector C375, wiring harness side, and ground.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to D3

→ No

LOCATE and REPAIR the open in the electrical circuit between the air recirculation flap positioning motor and ground point G41 using the wiring diagrams. CHECK the system for proper operation.

D3: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE AIR RECIRCULATION FLAP POSITIONING MOTOR

1Disconnect the C380 Heater Control Module.

2Measure the resistance between pin 16 of the heater control module connector C380, circuit 33-FA76 (YE/BU), wiring harness side and pin 1 of the recirculated air flap servo motor connector C375, circuit 33-FA76 (YE/BU) (RHD: pin 6, circuit 32-FA76 (WH/BU)), wiring harness side.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to D4

→ No

LOCATE and REPAIR the open in circuit 33-FA76 (YE/BL) or circuit 32-FA76 (WH/BL) between the heater control module and the recirculated air door positioning motor using the Wiring Diagrams. CHECK for proper system operation.

D4: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE AIR RECIRCULATION FLAP POSITIONING MOTOR

1Measure the resistance between pin 14 of the heater control module connector C380, circuit 32-FA76 (WH/BU), wiring harness side and pin 6 of the recirculated air flap servo motor connector C375, circuit 32-FA76 (WH/BU) (right-hand drive: pin 1, circuit 33-FA76 (YE/BU)), wiring harness side.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to D5

→ No

LOCATE and REPAIR the open in circuit 32-FA76 (WH/BU) or circuit 33-FA76 (YE/BU) between the heater control module and the recirculated air door positioning motor using the Wiring Diagrams. CHECK for proper system operation.

D5: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE AIR RECIRCULATION FLAP POSITIONING MOTOR AND THE HEATER CONTROL MODULE

1Measure the resistance between pin 4 of the heater control module connector C380, circuit 91S-FA90 (BK/GN), wiring harness side and pin 3 of the recirculated air flap positioning motor C375, circuit 91S-FA90 (BK/GN), wiring harness side.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to D6

→ No

LOCATE and REPAIR the open in circuit 91S-FA90 (Black/Green) between the heater control module and the recirculated air flap positioning motor using the Wiring Diagrams. CHECK for proper system operation.

D6: CHECKING THE HEATER CONTROL MODULE

NOTE:If the air distribution control switch is set to the defog/defrost position, the air recirculation mode cannot be switched on.

1Connect the C380 Heater Control Module.

2Enter the ON position.

3Turn on air recirculation.

4Measure the voltage between pins 1 and 6 of the air recirculation flap positioning motor connector C375, wiring harness side.

• Is the voltage registered at least 10V?

→ Yes

Go to D7

→ No

CHECK and REPLACE the heater control module if necessary. CHECK that the system is operating correctly.

D7: CHECKING THE HEATER CONTROL MODULE

1Turn off air recirculation.

2Measure the voltage again between pins 1 and 6 of the air recirculation flap positioning motor connector C375, wiring harness side.

• Has the voltage polarity changed?

→ Yes

CHECK the air recirculation flap for freedom of movement. If the air recirculation flap is mechanically OK, REPLACE the air recirculation flap positioning motor. CHECK the system for proper operation.

→ No

CHECK and if necessary REPLACE the heater control module. CHECK the system is operating correctly.

D8: CHECKING THE GROUNDING CIRCUIT OF THE AIR RECIRCULATION FLAP POSITIONING MOTOR

1Enter the OFF position.

2Disconnect C375 Air Recirculation Damper Positioning Motor.

3Measure the resistance between pin 3 of the air recirculation flap positioning motor connector C375, wiring harness side, and ground.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to D9

→ No

LOCATE and REPAIR the open in the electrical circuit between the air recirculation flap positioning motor and ground point G41 using the wiring diagrams. CHECK the system for proper operation.

D9: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE AIR RECIRCULATION FLAP POSITIONING MOTOR

1Disconnect the C380 Heater Control Module.

2Measure the resistance between pin 16 of the heater control module connector C380, circuit 33-FA76 (YE/BU), wiring harness side and pin 6 of the recirculated air flap servo motor connector C375, circuit 33-FA76 (YE/BU) (RHD: pin 1, circuit 32-FA76 (WH/BU)), wiring harness side.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to D10

→ No

LOCATE and REPAIR the open in circuit 33-FA76 (YE/BL) or circuit 32-FA76 (WH/BL) between the heater control module and the recirculated air door positioning motor using the Wiring Diagrams. CHECK for proper system operation.

D10: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE HEATER CONTROL MODULE AND THE AIR RECIRCULATION FLAP POSITIONING MOTOR

1Measure the resistance between pin 14 of the heater control module connector C380, circuit 32-FA76 (WH/BU), wiring harness side and pin 1 of the recirculated air flap servo motor connector C375, circuit 32-FA76 (WH/BU) (right-hand drive: pin 6, circuit 33-FA76 (YE/BU)), wiring harness side.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to D11

→ No

LOCATE and REPAIR the open in circuit 32-FA76 (WH/BU) or circuit 33-FA76 (YE/BU) between the heater control module and the recirculated air door positioning motor using the Wiring Diagrams. CHECK for proper system operation.

D11: CHECKING THE ELECTRICAL CIRCUIT BETWEEN THE AIR RECIRCULATION FLAP POSITIONING MOTOR AND THE HEATER CONTROL MODULE

1Measure the resistance between pin 4 of the recirculated air flap servo motor C375, circuit 91S-FA90 (BK/GN), wiring harness side and pin 4 of the heater control module C380, circuit 91S-FA90 (BK/GN), wiring harness side.

• Is the resistance registered less than 2 ohms?

→ Yes

Go to D12

→ No

LOCATE and REPAIR the open in circuit 91S-FA90 (Black/Green) between the heater control module and the recirculated air flap positioning motor using the Wiring Diagrams. CHECK for proper system operation.

D12: CHECKING THE HEATER CONTROL MODULE

NOTE:If the air distribution control switch is set to the defog/defrost position, the air recirculation mode cannot be switched on.

1Connect the C380 Heater Control Module.

2Enter the ON position.

3Turn on air recirculation.

4Measure the voltage between pins 1 and 6 of the air recirculation flap positioning motor connector C375, wiring harness side.

• Is the voltage registered at least 10V?

→ Yes

Go to D13

→ No

CHECK and if necessary REPLACE the heater control module. CHECK the system is operating correctly.

D13: CHECKING THE HEATER CONTROL MODULE

1Turn off air recirculation.

2Measure the voltage again between pins 1 and 6 of the air recirculation flap positioning motor connector C375, wiring harness side.

• Has the voltage polarity changed?

→ Yes

CHECK the air recirculation flap for freedom of movement. If the air recirculation flap is mechanically OK, REPLACE the air recirculation flap positioning motor. CHECK the system for proper operation.

→ No

CHECK and if necessary REPLACE the heater control module. CHECK the system is operating correctly.