Brake Lights (vehicles up to 08.2001) — Pinpoint Tests (Focus 1)

R1: CHECK FUSE F54

1CHECK F54.

• Is the fuse good?

→ Yes

Go to R2

→ No

REPLACE fuse F54. If fuse F54 fails again, LOCATE and REPAIR the short circuit using the wiring diagrams. CHECK the system for proper operation.

R2: CHECK VOLTAGE AT FUSE SECTION F54

1Enter the ON position.

2Measure the voltage between fuse F54 and ground.

• Does the meter show battery voltage?

→ Yes

Go to R3

→ No

Go to R9

R3: CHECK VOLTAGE AT THE STOP LIGHT SWITCH

1Disconnect C444.

2Enter the ON position.

3Measure the voltage at pin 3 of C444,.

• Does the meter show battery voltage?

→ Yes

Go to R4

→ No

REPAIR electrical circuit 15-LG23. CHECK correct system operation.

R4: CHECK STOP LIGHT SWITCH

1Disconnect C444.

2Enter the ON position.

3Use a suitable wire as a jumper between pins 3 and 1 of connector C444.

• Do the brake lights come on?

→ Yes

REPLACE the brake light switch. CHECK the system for proper operation.

→ No

Vehicles with Electronic Stability Program (ESP): Go to R5

Vehicles without Electronic Stability Program (ESP): REPAIR circuit 15S-LG14A (green/red) or 15S-LG14B (green/red). CHECK system operation for proper operation.

R5: CHECK STOP LIGHT RELAY

1Disconnect CBJB.

2Enter the ON position.

3Press the brake pedal.

4Check voltage at pin 3 of C1014 BJB.

• Does the meter show battery voltage?

→ Yes

Go to R6

→ No

REPAIR electrical circuit 15S-LG14B, 15S-CF58 or 15S-CF58A. CHECK proper system operation.

R6: CHECK STOP LIGHT RELAY

1Disconnect C1014 BJB.

2Enter the ON position.

3Press the brake pedal.

4Use a suitable wire as a jumper between pins 3 and 4 of the C1014 BJB connector.

• Do the brake lights come on?

→ Yes

Go to R7

→ No

REPAIR electrical circuit 15S-LG14A. CHECK correct system operation.

R7: CHECK STOP LIGHT RELAY

1Disconnect C1014 BJB.

2Enter the ON position.

3Check voltage at pin 1 of C1014 BJB.

• Does the meter show battery voltage?

→ Yes

Go to R8

→ No

REPAIR electrical circuit 15-CF58. CHECK for proper system operation.

R8: CHECK STOP LIGHT RELAY

1Disconnect C1014 BJB.

2Using an ohmmeter, measure the resistance between pin 2 of the C1014 BJB connector and ground.

• Is the measured resistance less than 2 ohms?

→ Yes

REPLACE the brake light relay. CHECK the system for proper operation.

→ No

REPAIR circuit 31S-CF71, if necessary REPLACE the Electronic Stability Program (ESP) module. CHECK the system for proper operation.

R9: CHECK POWER SUPPLY

1Disconnect Fuse F1.

2CHECK Fuse F1.

• Is fuse F1 in BJB OK?

→ Yes

Go to R10

→ No

REPLACE fuse F1. If fuse F1 fails again, LOCATE and REPAIR the short circuit using the wiring diagrams. CHECK the system for proper operation.

R10: CHECK POWER SUPPLY

1Enter the ON position.

2Measure the voltage at fuse F1.

• Does the meter show battery voltage?

→ Yes

REPAIR circuit 15-DA3 if necessary REPLACE CJB. CHECK system for proper operation.

→ No

REPAIR circuit 15-DC1, REPLACE ignition relay if necessary. CHECK system for proper operation.

S1: CHECK ADDITIONAL STOP LIGHT

1Enter the ON position.

2Press the brake pedal.

• Does the additional brake light come on?

→ Yes

Go to S4

→ No

Go to S2

S2: CHECK ELECTRICAL CIRCUIT 15S-LG6

1Enter the OFF position.

2Disconnect C107 additional brake lights.

3Enter the ON position.

4Press the brake pedal.

5Check the voltage between pin 1 of connector C107high-mounted brake lamp, circuit 15S-LG6 (GN/YE), harness side and ground.

• Does the meter show battery voltage?

→ Yes

Go to S3

→ No

REPAIR electrical circuit 15S-LG6. CHECK correct system operation.

S3: CHECK ELECTRICAL CIRCUIT OF MASSAGE 31-LG6

1Enter the OFF position.

2Check the resistance between pin 2 of the high brake light connector C107, circuit 31-LG6 (black), harness side and ground.

• Is the resistance less than 2 ohms?

→ Yes

After checking the bulb, REPLACE the additional brake light. CHECK the correct operation of the system.

→ No

REPAIR the 31-LG6 ground circuit. CHECK the system for proper operation.

S4: CHECK STOP LIGHTS

1Check the operation of the brake lights.

• Both brake lights not working?

→ Yes

REPAIR circuit 15S-LG14 (green/red), and/or REPAIR solder points S154 or S212. CHECK for proper system operation.

→ No

Right brake light not working: Go to S5

Left Brake Light Not Working: Go to S7

S5: CHECK ELECTRICAL CIRCUIT 15S-LG21

1Enter the OFF position.

2Disconnect C473, C475 and/or C477 right tail light assembly.

3Enter the ON position.

4Check the voltage between the right tail light assembly, circuit 15S-LG21 (green/black), harness side, and ground.

- 3-/5-door variants: pin 2 C473

- 4-door version: pin 2 C477

- "Universal": pin 1 C475

• Does the meter show battery voltage?

→ Yes

Go to S6

→ No

REPAIR electrical circuit 15S-LG21. CHECK correct system operation.

S6: CHECK GROUND CIRCUIT 31-LF24 / 31-LF4

1Enter the OFF position.

2Measure the resistance between the right tail light assembly, circuit 31-LF24 (black), 31-LF4, harness side, and ground.

- 3-/5-door variants: pin 3 C473

- 4-door version: pin 4 C477

- "Universal": pin 3 C475

• Is the resistance less than 2 ohms?

→ Yes

After checking the bulb, REPLACE the right tail light assembly. CHECK the system for proper operation.

→ No

REPAIR ground circuit 31-LF24 / 31-LF4 CHECK system for proper operation.

S7: CHECK ELECTRICAL CIRCUIT 15S-LG14A

1Enter the OFF position.

2Disconnect C472, C474 and/or C476 from the tail light assembly.

3Enter the ON position.

4Check the voltage between the left tail light assembly, circuit 15S-LG14A (green/red), harness side, and ground.

- 3-/5-door variants: pin 2 C472

- 4-door version: pin 1 C476

- "Universal": pin 1 C474

• Does the meter show battery voltage?

→ Yes

Go to S6

→ No

REPAIR electrical circuit 15S-LG14A. CHECK correct system operation.

S8: CHECK EARTH CIRCUIT 31-LF23 / 31-DA18

1Enter the OFF position.

2Measure the resistance between the left tail light assembly, circuit 31-LF23 (black) / 31-DA18 (black), harness side, and ground.

- 3-/5-door variants: pin 3 C472

- 4-door version: pin 6 C476

- "Universal": pin 3 C474

• Is the resistance less than 2 ohms?

→ Yes

After checking the bulb, REPLACE the left tail light assembly. CHECK the system for proper operation.

→ No

REPAIR ground circuit 31-LF23 / 31-DA18 CHECK system operation for proper operation.

T1: CHECK ELECTRICAL CIRCUIT(S)

1Disconnect Connector C51.

2Enter the ON position.

• Are the brake lights on all the time?

→ Yes

REPAIR circuit 15S-LG21 (green/black), 15S-LG14A (green/red), 15S-LG14 (green/red), or 15S-LG6 (green/yellow). CHECK for proper system operation.

→ No

Go to T2

T2: CHECK STOP LIGHT SWITCH

1Disconnect Connector C444.

2Enter the ON position.

• Do the brake lights come on?

→ Yes

Vehicles without Electronic Stability Program: Go to T3

Vehicles with Electronic Stability Program: Go to T6

→ No

REPLACE the brake light switch. CHECK the system for proper operation.

T3: CHECK MODULES

1Disconnect C385 ABS Control Module.

2Disconnect Powertrain Control Module C415.

3Disconnect C831 speed control module.

• Are the brake lights on all the time?

→ Yes

REPAIR electrical circuits 15S-CF58, 15S-LG14B, 15S-LG14A, 15S-RN₂, 15S-RE13 or 15S-PG17. CHECK proper system operation.

→ No

Go to T4

T4: CHECK ABS CONTROL MODULE

1Connect the ABS Control Module.

2Enter the ON position.

• Are the brake lights on all the time?

→ Yes

REPLACE the ABS control module. CHECK the system for proper operation.

→ No

Go to T5

T5: CHECK POWERTRAIN CONTROL MODULE (PCM)

1Connect the Powertrain Control Module (PCM).

2Enter the ON position.

• Are the brake lights on all the time?

→ Yes

REPLACE the powertrain control module (PCM) CHECK the system for proper operation.

→ No

REPLACE the speed control module. CHECK the system for proper operation.

T6: CHECK ELECTRICAL CIRCUIT 15S-LG14A

1Disconnect C1014 BJB.

2Enter the ON position.

• Are the brake lights on all the time?

→ Yes

REPAIR electrical circuit 15S-LG14A to C51. CHECK system operation for proper operation.

→ No

Go to T7

T7: CHECK MODULES

1Disconnect the C830 Electronic Stability Program module.

2Disconnect Powertrain Control Module C415.

3Disconnect C831 speed control module.

4Enter the ON position.

• Are the brake lights on all the time?

→ Yes

REPAIR electrical circuit 15S-PG7, 15S-PG17, 15S-RE13, 15S-RN₂, 15S-CF58 or 15S-CF58A. CHECK proper system operation.

→ No

Go to T8

T8: CHECK ELECTRONIC STABILITY PROGRAM (ESP) MODULE

1Connect the Electronic Stability Program (ESP) Module.

2Enter the ON position.

• Are the brake lights on all the time?

→ Yes

REPLACE the Electronic Stability Program (ESP) module. CHECK the system for proper operation.

→ No

Go to T5