Inspection Procedure H-7

INSPECTION PROCEDURE H-7: Headlight and Taillight: One of the headlights does not illuminate.


















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
- MB992006: Extra Fine Probe

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

- Check the ground wire for open circuit.





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). 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.

- Check the ground wire for open circuit.





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). 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).

- Check the communication lines for open circuit and short circuit.









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). 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).

- Check the communication lines for open circuit and short circuit.









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). 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).

- Check the communication lines for open circuit and short circuit.









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). 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).

- Check the communication lines for open circuit and short circuit.









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.