Inspection Procedure J-7

One of the headlights does not illuminate.

Headlights Circuit Part 1:

Headlights Circuit 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: Test 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 12.
LH (only high beam): Go to Step 16.
RH (only high beam): Go to Step 20.
Low beam only (both RH and LH): Refer to Inspection Procedure J-2 "Headlights (low-beam) do not illuminate normally."
High beam (both RH and LH): Refer to Inspection Procedure J-3 "Headlights (high-beam) do not illuminate normally."
Only high-beam indicator light: Refer to Inspection Procedure J-8 "High-beam indicator light does not illuminate.




STEP 2. Check headlight (LH) connector A-24 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is headlight (LH) connector A-24 in good condition?

YES: Go to Step 3.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Verify 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-24 (terminal 2) and ground.

Q: Is the wiring harness between headlight (LH) connector A-24 (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-35 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is headlight (RH) connector A-35 in good condition?

YES: Go to Step 6.

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

STEP 6. Check 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 bulb (RH). Verify that the headlights illuminate normally.




STEP 7. Check the wiring harness between headlight (RH) connector A-35 (terminal 2) and ground.

Q: Is the wiring harness between headlight (RH) connector A-35 (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-24 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is headlight (LH) connector A-24 in good condition?

YES: Go to Step 9.

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




STEP 10. Check front-ECU connector A-10X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is front-ECU connector A-10X in good condition?

YES: Go to Step 11.

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







STEP 11. Check the wiring harness between headlight (LH) connector A-24 (terminal 1) and front-ECU connector A-10X (terminal 6).

Q: Is the wiring harness between headlight (LH) connector A-24 (terminal 1) and front-ECU connector A-10X (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 12. Check headlight (RH) connector A-35 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is headlight (RH) connector A-35 in good condition?

YES: Go to Step 13.

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

STEP 13. Check 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 14.

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




STEP 14. Check front-ECU connector A-10X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is front-ECU connector A-10X 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 the wiring harness between headlight (RH) connector A-35 (terminal 1) and front-ECU connector A-10X (terminal 6).

NOTE: Also check intermediate connector C-06 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-06 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection.

Q: Is the wiring harness between headlight (RH) connector A-35 (terminal 1) and front-ECU connector A-10X (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 16. Check headlight (LH) connector A-24 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is headlight (LH) connector A-24 in good condition?

YES: Go to Step 17.

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

STEP 17. 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 18.

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




STEP 18. Check A-10X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is front-ECU connector A-10X in good condition?

YES: Go to Step 19.

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







STEP 19. Check the wiring harness between headlight (LH) connector A-24 (terminal 3) and front-ECU connector A-10X (terminal 2).

Q: Is the wiring harness between headlight (LH) connector A-24 (terminal 3) and front-ECU connector A-10X (terminal 2) 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 20. Check headlight (RH) connector A-35 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is headlight (RH) connector A-35 in good condition?

YES: Go to Step 21.

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

STEP 21. Check 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 22.

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




STEP 22. Check front-ECU connector A-10X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is front-ECU connector A-10X in good condition?

YES: Go to Step 23.

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










STEP 23. Check the wiring harness between headlight (RH) connector A-35 (terminal 3) and front-ECU connector A-10X (terminal 2).

NOTE: Also check intermediate connector C-06 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-06 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection.

Q: Is the wiring harness between headlight (RH) connector A-35 (terminal 3) and front-ECU connector A-10X (terminal 2) 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.