Inspection Procedure H-7

Headlight and Taillight: One of the headlights does not illuminate. <2-bulb type>

TECHNICAL DESCRIPTION (COMMENT)
If one of the headlights does not illuminate, a headlight bulb may be defective.

TROUBLESHOOTING HINTS
- The headlight bulb may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

Required Special Tool:
- MB991223: Harness Set

STEP 1. Check the headlight operation.

Q : Which of the headlights does not illuminate?
LH (low and high beam) : Go to Step 2.
RH (low and high beam) : Go to Step 5.
LH (only low-beam) : Go to Step 8.
RH (only low-beam) : Go to Step 11.
LH (only high beam) : Go to Step 14.
RH (only high beam) : Go to Step 17.

Low beam only (both RH and LH) : Refer to Inspection Procedure H-2 "The headlights (low-beam) do not illuminate normally."

High beam only (both RH and LH) : Refer to Inspection Procedure H-3 "The headlights (high-beam) do not illuminate normally."

High beam indicator light : Refer to Inspection Procedure H-8 "The high-beam indicator light does not illuminate."

STEP 2. Check headlight (LH) connector A-19 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is headlight (LH) connector A-19 in good condition?

YES : Go to Step 3.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlights illuminate normally.

STEP 3. Check headlight (LH) bulb.

1. Remove the headlight (LH) bulb.
2. Verify that the headlight (LH) bulb is not damaged or burned out.

Q : Is headlight (LH) bulb normal?

YES : Go to Step 4.

NO : Replace the headlight (LH) bulb. Verify that the headlights illuminate normally.

STEP 4. Check the wiring harness between headlight (LH) connector A-19 (terminal 2) and ground.

Q : Is the wiring harness between headlight (LH) connector A-19 (terminal 2) and ground in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlights illuminate normally.

STEP 5. Check headlight (RH) connector A-33 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is headlight (RH) connector A-33 in good condition?

YES : Go to Step 6.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlights illuminate normally.

STEP 6. Check the headlight (RH) bulb.

1. Remove the headlight (RH) bulb.
2. Verify that the headlight (RH) bulb is not damaged or burned out.

Q : Is headlight (RH) bulb normal?

YES : Go to Step 7.

NO : Replace the headlight (RH) bulb. Verify that the headlights illuminate normally.

STEP 7. Check the wiring harness between headlight (RH) connector A-33 (terminal 2) and ground.

Q : Is the wiring harness between headlight (RH) connector A-33 (terminal 2) and ground in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlights illuminate normally.

STEP 8. Check headlight (LH) connector A-19 and front-ECU connector A-11X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Are headlight (LH) connector A-19 and front-ECU connector A-11X in good condition?

YES : Go to Step 9.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlights illuminate normally.

STEP 9. Check headlight (LH) bulb.

1. Remove the headlight (LH) bulb.
2. Verify that the headlight (LH) bulb is not damaged or burned out.

Q : Is headlight (LH) bulb normal?

YES : Go to Step 10.

NO : Replace the headlight (LH) bulb. Verify that the headlights illuminate normally.

STEP 10. Check the wiring harness between headlight (LH) connector A-19 (terminal 1) and front-ECU connector A-11X (terminal 6).

Q : Is the wiring harness between headlight (LH) connector A-19 (terminal 1) and front-ECU connector A-11X (terminal 6) in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlights illuminate normally.

STEP 11. Check headlight (RH) connector A-33 and front-ECU connector A-11X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Are headlight (RH) connector A-33 and front-ECU connector A-11X in good condition?

YES : Go to Step 12.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlights illuminate normally.

STEP 12. Check the headlight (RH) bulb.

1. Remove the headlight (RH) bulb.
2. Verify that the headlight (RH) bulb is not damaged or burned out.

Q : Is headlight (RH) bulb normal?

YES : Go to Step 13.

NO : Replace the headlight (RH) bulb. Verify that the headlights illuminate normally.

STEP 13. Check the wiring harness between headlight (RH) connector A-33 (terminal 1) and front-ECU connector A-11X (terminal 6).

Q : Is the wiring harness between headlight (RH) connector A-33 (terminal 1) and front-ECU connector A-11X (terminal 6) in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlights illuminate normally.

STEP 14. Check headlight (LH) connector A-19 and front-ECU connector A-11X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Are headlight (LH) connector A-19 and front-ECU connector A-11X in good condition?

YES : Go to Step 15.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Verify that the headlights illuminate normally.

STEP 15. Check headlight (LH) bulb.

1. Remove the headlight (LH) bulb.
2. Verify that the headlight (LH) bulb is not damaged or burned out.

Q : Is headlight (LH) bulb normal?

YES : Go to Step 16.

NO : Replace the headlight (LH) bulb. Verify that the headlights illuminate normally.

STEP 16. Check the wiring harness between headlight (LH) connector A-19 (terminal 3) and front-ECU connector A-11X (terminal 10).

Q : Is the wiring harness between headlight (LH) connector A-19 (terminal 3) and front-ECU connector A-11X (terminal 10) in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlights illuminate normally.

STEP 17. Check headlight (RH) connector A-33 and front-ECU connector A-11X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Are headlight (RH) connector A-33 and front-ECU connector A-11X in good condition?

YES : Go to Step 18.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Verify that the headlights illuminate normally.

STEP 18. Check the headlight (RH) bulb.

1. Remove the headlight (RH) bulb.
2. Verify that the headlight (RH) bulb is not damaged or burned out.

Q : Is headlight (RH) bulb normal?

YES : Go to Step 19.

NO : Replace the headlight (RH) bulb. Verify that the headlights illuminate normally.

STEP 19. Check the wiring harness between headlight (RH) connector A-33 (terminal 3) and front-ECU connector A-11X (terminal 10).

Q : Is the wiring harness between headlight (RH) connector A-33 (terminal 3) and front-ECU connector A-11X (terminal 10) in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlights illuminate normally.

Headlight and Taillight: One of the headlights does not illuminate. <4-bulb type>

Part 1:

Part 2:

TECHNICAL DESCRIPTION (COMMENT)
If one of the headlights does not illuminate, a headlight bulb may be defective.

TROUBLESHOOTING HINTS
- The headlight bulb may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

Required Special Tool:
- MB991223: Harness Set

STEP 1. Check the headlight operation.

Q : Which of the headlights does not illuminate?

Low (LH) : Go to Step 2.
Low (RH) : Go to Step 8.
High (LH) : Go to Step 14.
High (RH) : Go to Step 20.
Low beam only (both RH and LH) : Refer to Inspection Procedure H-2 "The headlights (low-beam) do not illuminate normally."
High beam only (both RH and LH) : Refer to Inspection Procedure H-3 "The headlights (high-beam) do not illuminate normally."
High beam indicator light : Refer to Inspection Procedure H-8 "The high-beam indicator light does not illuminate."

STEP 2. Check headlight (LOW: LH) connector A-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is headlight (LOW: LH) connector A-20 in good condition?

YES : Go to Step 3.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlight (LOW: LH) illuminates normally.

STEP 3. Check the headlight bulb (LOW: LH).

1. Remove the headlight bulb (LOW: LH).
2. Verify that the headlight bulb (LOW: LH) is not damaged or burned out.

Q : Is the headlight bulb (LOW: LH) in good condition?

YES : Go to Step 4.

NO : Replace the headlight bulb (LOW: LH). Verify that the headlight (LOW: LH) illuminates normally.

STEP 4. Check the ground circuit to the headlight (LOW: LH). Measure the resistance at headlight (LOW: LH) connector A-20.

1. Disconnect headlight (LOW: LH) connector A-20 and measure the resistance available at the wiring harness side of the connector.

2. Measure the resistance value between terminal 2 and ground.
- The resistance should be 2 ohms or less.

Q : Is the measured resistance 2 ohms or less?

YES : Go to Step 6.

NO : Go to Step 5.

STEP 5. Check the wiring harness between headlight (LOW: LH) connector A-20 (terminal 2) and ground.

Q : Is the wiring harness between headlight (LOW: LH) connector A-20 (terminal 2) and ground in good condition?

YES : Replace the headlight socket (LOW: LH). Verify that the headlight (LOW: LH) illuminates normally.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlight (LOW: LH) illuminates normally.

STEP 6. Check front-ECU connector A-11X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is front-ECU connector A-11X in good condition?

YES : Go to Step 7.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlight (LOW: LH) illuminates normally.

STEP 7. Check the wiring harness between headlight (LOW: LH) connector A-20 (terminal 1) and front-ECU connector A-11X (terminal 6).

Q : Is the wiring harness between headlight (LOW: LH) connector A-20 (terminal 1) and front-ECU connector A-11X (terminal 6) in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlight (LOW: LH) illuminates normally.

STEP 8. Check headlight (LOW: RH) connector A-32 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is headlight (LOW: RH) connector A-32 in good condition?

YES : Go to Step 9.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlight (LOW: RH) illuminates normally.

STEP 9. Check the headlight bulb (LOW: RH).

1. Remove the headlight bulb (LOW: RH).
2. Verify that the headlight bulb (LOW: RH) is not damaged or burned out.

Q : Is the headlight bulb (LOW: RH) in good condition?

YES : Go to Step 10.

NO : Replace the headlight bulb (LOW: RH). Verify that the headlight (LOW: RH) illuminates normally.

STEP 10. Check the ground circuit to the headlight (LOW: RH). Measure the resistance at headlight (LOW: RH) connector A-32.

1. Disconnect headlight (LOW: RH) connector A-32 and measure the resistance available at the wiring harness side of the connector.

STEP 11. Check the wiring harness between headlight (LOW: RH) connector A-32 (terminal 2) and ground.

Q : Is the wiring harness between headlight (LOW: RH) connector A-32 (terminal 2) and ground in good condition?

YES : Replace the headlight socket (LOW: RH). Verify that the headlight (LOW: RH) illuminates normally.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlight (LOW: RH) illuminates normally.

STEP 12. Check front-ECU connector A-11X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is front-ECU connector A-11X in good condition?

YES : Go to Step 13.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlight (LOW: RH) illuminates normally.

STEP 13. Check the wiring harness between headlight (LOW: RH) connector A-32 (terminal 1) and front-ECU connector A-11X (terminal 6).

Q : Is the wiring harness between headlight (LOW: RH) connector A-32 (terminal 1) and front-ECU connector A-11X (terminal 6) in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlight (LOW: RH) illuminates normally.

STEP 14. Check headlight (HIGH: LH) connector A-21 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is headlight (HIGH: LH) connector A-21 in good condition?

YES : Go to Step 15.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlight (HIGH: LH) illuminates normally.

STEP 15. Check the headlight bulb (HIGH: LH).

1. Remove the headlight bulb (HIGH: LH).
2. Verify that the headlight bulb (HIGH: LH) is not damaged or burned out.

Q : Is the headlight bulb (HIGH: LH) in good condition?

YES : Go to Step 16.

NO : Replace the headlight bulb (HIGH: LH). Verify that the headlight (HIGH: LH) illuminates normally.

STEP 16. Check the ground circuit to the headlight (HIGH: LH). Measure the resistance at headlight (HIGH: LH) connector A-21.

1. Disconnect headlight (HIGH: LH) connector A-21 and measure the resistance available at the wiring harness side of the connector.

STEP 17. Check the wiring harness between headlight (HIGH: LH) connector A-21 (terminal 2) and ground.

Q : Is the wiring harness between headlight (HIGH: LH) connector A-21 (terminal 2) and ground in good condition?

YES : Replace the headlight socket (HIGH: LH). Verify that the headlight (HIGH: LH) illuminates normally.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlight (HIGH: LH) illuminates normally.

STEP 18. Check front-ECU connector A-11X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is front-ECU connector A-11X in good condition?

YES : Go to Step 19.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlight (HIGH: LH) illuminates normally.

STEP 19. Check the wiring harness between headlight (HIGH: LH) connector A-21 (terminal 1) and front-ECU connector A-11X (terminal 10).

Q : Is the wiring harness between headlight (HIGH: LH) connector A-21 (terminal 1) and front-ECU connector A-11X (terminal 10) in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlight (HIGH: LH) illuminates normally.

STEP 20. Check headlight (HIGH: RH) connector A-31 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is headlight (HIGH: RH) connector A-31 in good condition?

YES : Go to Step 21.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlight (HIGH: RH) illuminates normally.

STEP 21. Check the headlight bulb (HIGH: RH).

1. Remove the headlight bulb (HIGH: RH).
2. Verify that the headlight bulb (HIGH: RH) is not damaged or burned out.

Q : Is the headlight bulb (HIGH: RH) in good condition?

YES : Go to Step 22.

NO : Replace the headlight bulb (HIGH: RH). Verify that the headlight (HIGH: RH) illuminates normally.

STEP 22. Check the ground circuit to the headlight (HIGH: RH). Measure the resistance at headlight (HIGH: RH) connector A-31.

1. Disconnect headlight (HIGH: RH) connector A-31 and measure the resistance available at the wiring harness side of the connector.

STEP 23. Check the wiring harness between headlight (HIGH: RH) connector A-31 (terminal 2) and ground.

Q : Is the wiring harness between headlight (HIGH: RH) connector A-31 (terminal 2) and ground in good condition?

YES : Replace the headlight socket (HIGH: RH). Verify that the headlight (HIGH: RH) illuminates normally.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlight (HIGH: RH) illuminates normally.

STEP 24. Check front-ECU connector A-11X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is front-ECU connector A-11X in good condition?

YES : Go to Step 25.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Check that the headlight (HIGH: RH) illuminates normally.

STEP 25. Check the wiring harness between headlight (LOW: RH) connector A-32 (terminal 1) and front-ECU connector A-11X (terminal 10).

Q : Is the wiring harness between headlight (LOW: RH) connector A-32 (terminal 1) and front-ECU connector A-11X (terminal 10) in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the headlight (HIGH: RH) illuminates normally.