Brake Lights (Cars after 08.2001) — Pinpoint Tests (Focus 1)

U1: CHECKING FUSE F42 (CJB)

1Enter the OFF position.

2CHECK Fuse F42 (CJB).

3Check fuse F42 (15 A).

• Is the fuse good?

→ Yes

Go to U2

→ No

INSTALL a new fuse F42 (15A) and CHECK the system for proper operation. If the fuse blows again, LOCATE and REPAIR the short circuit using the wiring diagrams. CHECK the system for proper operation.

U2: CHECKING THE VOLTAGE AT FUSE F42 (CJB)

1Connect Fuse F42 (CJB).

2Enter the ON position.

3Measure the voltage between F42 (CJB) and ground.

• Is battery voltage registered?

→ Yes

Go to U3

→ No

Using the wiring diagrams, RESTORE the power supply to fuse F42. If necessary, INSTALL a new CJB. Check that the system is operating correctly.

U3: CHECKING THE VOLTAGE IN THE STOP LIGHT SWITCH

1Enter the OFF position.

2Disconnect C444 brake light switch.

3Enter the ON position.

4Measure the voltage between pin 3 of the brake light switch connector C444, circuit 15-LG23 (GN/WH), harness side and ground.

• Is battery voltage registered?

→ Yes

Go to U4

→ No

LOCATE and using the wiring diagrams REPAIR the open in the 15-LG23 (Green/White) circuit between fuse F42 and the brake light switch. Check for proper system operation.

U4: CHECKING THE STOP LIGHT SWITCH

1Enter the OFF position.

2Install a fused jumper wire (15 A) into brake light switch connector C444 between pin 3, circuit 15-LG23 (GN/W) and pin 1, circuit 15S-LG41B (GN/R) on the harness side.

3Enter the ON position.

4Check the brake lights.

• Are the brake lights on?

→ Yes

INSTALL a new brake light switch. Check that the system operates correctly.

→ No

LOCATE and, using the wiring diagrams, REPAIR the open in the 15S-LG41B (GN/RD) and 15S-LG41A (GN/RD) circuit between the brake light switch and splice S154. Check for proper system operation.

V1: DETERMINING THE STATE IN WHICH THE MALFUNCTION OCCURS

1Enter the ON position.

2Turn on the STOP LIGHTS.

3Check the brake lights.

• High brake light not working?

→ Yes

Go to V2

→ No

Go to V3

V2: CHECKING THE HIGH BRAKE LIGHT

1Enter the OFF position.

2Disconnect C107 high brake light.

3Enter the ON position.

4Turn on the STOP LIGHTS.

5Measure the voltage between pin 1 of connector C107 high mounted stop lamp, circuit 15S-LG6 (GN/YE), harness side and ground.

• Is battery voltage registered?

→ Yes

LOCATE and, using the wiring diagrams, REPAIR the open in circuit 31-LG6 (Black) between the high mounted brake lamp and grounds G35 and G15. INSTALL a new high mounted brake lamp as needed. Check for proper system operation.

→ No

LOCATE and, using the wiring diagrams, REPAIR the open in circuit 15S-LG6 (GN/YE) between splice S154 and the high mounted brake light. INSTALL a new high mounted brake light if necessary. Check for proper system operation.

V3: DETERMINE THE STATE IN WHICH THE MALFUNCTION OCCURS.

1Enter the ON position.

2Turn on the STOP LIGHTS.

3Check the brake lights.

• Both brake lights not working?

→ Yes

Go to V4

→ No

Left side: Go to V5

Right side: Go to V6

V4: CHECKING THE ELECTRICAL POWER SUPPLY CIRCUIT OF THE LEFT REAR LAMP ASSEMBLY

1Enter the OFF position.

2Disconnect the Left Tail Light Assembly.

- C472 (3-door/5-door version)

- C474 ("Universal")

- C476 (4-door version)

3Enter the ON position.

4Turn on the STOP LIGHTS.

5Measure the voltage between pin 1 of connector C474 and respectively connector C476 (respectively pin 2 of connector C472) of the left rear light assembly, electrical circuit 15S-LG14A (green-red), on the wiring side, and ground.

• Is battery voltage registered?

→ Yes

LOCATE and, using the wiring diagrams, REPAIR the open in circuit 31-DA18 (Black) between splice S184 and ground G46. INSTALL a new tail lamp assembly as needed. Check for proper system operation.

→ No

LOCATE and, using the wiring diagrams, REPAIR the open in circuit 15S-LG14 (Green/Red) between splice S154 and splice S116 (tail lamp assembly). INSTALL a new tail lamp assembly if necessary. Check for proper system operation.

V5: CHECKING THE ELECTRICAL POWER SUPPLY CIRCUIT OF THE LEFT REAR LAMP ASSEMBLY

1Enter the OFF position.

2Disconnect the Left Tail Light Assembly.

- C472 (3-door/5-door version)

- C474 ("Universal")

- C476 (4-door version)

3Enter the ON position.

4Turn on the STOP LIGHTS.

5Measure the voltage between pin 1 of connector C474 and respectively connector C476 (respectively pin 2 of connector C472) of the left rear light assembly, electrical circuit 15S-LG14A (green-red), on the wiring side, and ground.

• Is battery voltage registered?

→ Yes

LOCATE and, using the wiring diagrams, REPAIR the open in circuit 31-LF23 (Black) between the tail lamp assembly and splice S184. INSTALL a new tail lamp assembly as needed. Check for proper system operation.

→ No

LOCATE and, using the wiring diagrams, REPAIR the open in circuit 15S-LG14A (Green/Red) between splice S116 and tail lamp assembly. INSTALL a new tail lamp assembly if necessary. Check for proper system operation.

V6: CHECKING THE ELECTRICAL POWER SUPPLY CIRCUIT OF THE RIGHT TAIL LAMP ASSEMBLY

1Enter the OFF position.

2Disconnect the Right Tail Light Assembly.

- C473 (3-door/5-door version)

- C475 ("Universal")

- C477 (4-door version)

3Enter the ON position.

4Turn on the STOP LIGHTS.

5Measure the voltage between pin 1 of connector C475 and respectively connector C477 (respectively pin 2 of connector C473) of the right rear lamp assembly, electrical circuit 15S-LG21 (green/black), harness side, and ground.

• Is battery voltage registered?

→ Yes

LOCATE and, using the wiring diagrams, REPAIR the open in circuit 31-LF24 (Black) between the tail lamp assembly and splice S184. INSTALL a new tail lamp assembly as needed. Check for proper system operation.

→ No

LOCATE and, using the wiring diagrams, REPAIR the open in circuit 15S-LG21 (Green/Black) between splice S116 and tail lamp assembly. INSTALL a new tail lamp assembly if necessary. Check for proper system operation.

W1: CHECKING THE STOP LIGHT SWITCH

1Enter the OFF position.

2Disconnect C444 brake light switch.

3Enter the ON position.

4Check the brake lights.

• Are the brake lights on?

→ Yes

Go to W2

→ No

INSTALL a new brake light switch. Check that the system operates correctly.

W2: CHECKING THE SYSTEM USING WDS

1Enter the OFF position.

2Connect C444 brake light switch.

3Connect the diagnostic tool.

4Check the system using WDS.

• Are there any diagnostic trouble codes (DTCs)?

→ Yes

PERFORM the necessary DTC actions according to the WDS instructions. CLEAR the fault memory and CHECK the system for proper operation.

→ No

Go to W3

W3: RULING OUT THE SHORT CIRCUIT CONDITION TO POWER SUPPLY POSSIBLY CAUSED BY ABS MODULE, ESP MODULE, EEC MODULE TAKE ACTIONS APPROPRIATELY

1Enter the OFF position.

2Disconnect each of the listed items one at a time and then proceed with the following inspection procedures (steps 3 and 4):.

-.C840 ABS module

- C840 ABS/ESP module (with ESP)

- C831 Speed Control Module (with speed control system)

- C415 Powertrain Control Module (Common Rail Diesel Engine Only)

3Enter the ON position.

4Check the brake lights.

• Are the brake lights on all the time?

→ Yes

Not all relevant components are disconnected: Turn off the ignition. Disconnect the next component (go to step 2).

All relevant components disconnected: Using the electrical connection diagrams, FIND and REPAIR the short circuit to the power supply in the electrical circuits connected to splices S2, S154 and S216. Check the correct operation of the system.

→ No

REPLACE the last disconnected element. Check the system for proper operation.