Inspection Procedure I-7
Headlight, Tail Light: One of the headlights does not illuminateHeadlight Circuit:
Connectors:
TECHNICAL DESCRIPTION (COMMENT)
If one of the headlights does not illuminate, a headlight bulb may be defective.
TROUBLESHOOTING HINTS
- Malfunction of headlight bulb
- Damaged harness wires or connectors
DIAGNOSIS
Required Special Tools:
- 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 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 I-2 "Headlights (low-beam) do not illuminate."
High beam (both RH and LH) and high-beam indicator light : Refer to Inspection Procedure I-3 "Headlights (high-beam) do not illuminate."
Only high-beam indicator light: Refer to Inspection Procedure I-8 "The high-beam indicator light does not illuminate."
STEP 2. Check headlight (LH) bulb.
1. Remove the headlight (LH) bulb.
2. Check that the headlight (LH) bulb is not broken.
Q: Is headlight (LH) bulb normal?
YES: Go to Step 3.
NO: Replace the headlight (LH) bulb. Check that the headlights illuminate normally.
STEP 3. Check headlight (LH) connector A-15 for damage.
Q: Is headlight (LH) connector A-15 in good condition?
YES: Go to Step 4.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the headlights illuminate normally.
STEP 4. Check the wiring harness between headlight (LH) connector A-15 and ground.
Q: Is the wiring harness between headlight (LH) connector A-15 and ground in good condition?
YES: No action to be taken.
NO: Repair the wiring harness. Check that the headlights illuminate normally.
STEP 5. Check headlight (RH) bulb.
1. Remove the headlight (RH) bulb.
2. Check that the headlight (RH) bulb is not broken.
Q: Is headlight (RH) bulb normal?
YES: Go to Step 6.
NO: Replace the headlight (RH) bulb. Check that the headlights illuminate normally.
STEP 6. Check headlight (RH) connector A-21 for damage.
Q: Is headlight (RH) connector A-21 in good condition?
YES: Go to Step 7.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the headlights illuminate normally.
STEP 7. Check the wiring harness between headlight (RH) connector A-21 and ground.
Q: Is the wiring harness between headlight (RH) connector A-21 and ground in good condition?
YES: No action to be taken.
NO: Repair the wiring harness. Check that the headlights illuminate normally.
STEP 8. Check headlight (LH) bulb.
1. Remove the headlight (LH) bulb.
2. Check that the headlight (LH) bulb is not broken.
Q: Is headlight (LH) bulb normal?
YES: Go to Step 9.
NO: Replace the headlight (LH) bulb. Check that the headlights illuminate normally.
STEP 9. Check headlight (LH) connector A-15 and front-ECU connector A-10X for damage.
Q: Are headlight (LH) connector A-15 and front-ECU connector A-10X in good condition?
YES: Go to Step 10.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the headlights illuminate normally.
STEP 10. Check the wiring harness between headlight (LH) connector A-15 and front-ECU connector A-10X.
Q: Is the wiring harness between headlight (LH) connector A-15 and front-ECU connector A-10X in good condition?
YES: No action to be taken.
NO: Repair the wiring harness. Check that the headlights illuminate normally.
STEP 11. Check headlight (RH) bulb.
1. Remove the headlight (RH) bulb.
2. Check that the headlight (RH) bulb is not broken.
Q: Is headlight (RH) bulb normal?
YES: Go to Step 12.
NO: Replace the headlight (RH) bulb. Check that the headlights illuminate normally.
STEP 12. Check headlight (RH) connector A-21 and front-ECU connector A-10X for damage.
Q: Are headlight (RH) connector A-21 and front-ECU connector A-10X in good condition?
YES: Go to Step 13.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the headlights illuminate normally.
STEP 13. Check the wiring harness between headlight (RH) connector A-21 and front-ECU connector A-10X.
NOTE: Also check intermediate connectors C-129 and C-111. If intermediate connectors C-129 or C-111 is damaged, repair or replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between headlight (RH) connector A-21 and front-ECU connector A-10X in good condition?
YES: No action to be taken.
NO: Repair the wiring harness. Check that the headlights illuminate normally.
STEP 14. Check headlight (LH) bulb.
1. Remove the headlight (LH) bulb.
2. Check that the headlight (LH) bulb is not broken.
Q: Is headlight (LH) bulb normal?
YES: Go to Step 15.
NO: Replace the headlight (LH) bulb. Check that the headlights illuminate normally.
STEP 15. Check headlight (LH) connector A-15 and front-ECU connector A-10X for damage.
Q: Are headlight (LH) connector A-15 and front-ECU connector A-10X in good condition?
YES: Go to Step 16.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the headlights illuminate normally.
STEP 16. Check the wiring harness between headlight (LH) connector A-15 and front-ECU connector A-10X.
Q: Is the wiring harness between headlight (LH) connector A-15 and front-ECU connector A-10X in good condition?
YES: No action to be taken.
NO: Repair the wiring harness. Check that the headlights illuminate normally.
STEP 17. Check headlight (RH) bulb.
1. Remove the headlight (RH) bulb.
2. Check that the headlight (RH) bulb is not broken.
Q: Is headlight (RH) bulb normal?
YES: Go to Step 18.
NO: Replace the headlight (RH) bulb. Check that the headlights illuminate normally.
STEP 18. Check headlight (RH) connector A-21 and front-ECU connector A-10X for damage.
Q: Are headlight (RH) connector A-21 and front-ECU connector A-10X in good condition?
YES: Go to Step 19.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the headlights illuminate normally.
STEP 19. Check the wiring harness between headlight (RH) connector A-21 and front-ECU connector A-10X.
NOTE: Also check intermediate connectors C-129 and C-111. If intermediate connectors C-129 or C-111 is damaged, repairer replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between headlight (RH) connector A-21 and front-ECU connector A-10X in good condition?
YES: No action to be taken.
NO: Repair the wiring harness. Check that the headlights illuminate normally.