Inspection Procedure J-7

Headlight and Taillight: One of the headlights does not illuminate.

Headlights Circuit <Discharge Headlight>:

Headlights Circuit <Halogen Headlight> Part 1:

Headlights Circuit <Halogen Headlight> Part 2:

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

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

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?

Low-beam (LH and/or RH): Refer to Headlight, Side Marker Light and Position Light Assembly - Lighting System Diagnosis.

Low beam (LH): Go to Step 2.

Low beam (RH): Go to Step 7.

High beam (LH): Go to Step 12.

High beam (RH): Go to Step 17.

High-beam indicator light: Go to Step 22.

High beam (both RH and LH) and high-beam indicator light : Refer to Inspection Procedure J-3 "Headlights (high-beam) do not illuminate."

STEP 2. Check front combination light assembly (LH) connector A-41 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is front combination light assembly (LH) connector A-41 in good condition?

YES: Go to Step 3.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. Verify that the headlight (LOW: LH) illuminate normally.

STEP 3. Check 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 headlight bulb (LOW: LH) normal?

YES: Go to Step 4.

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

STEP 4. Check the ground circuit to the headlight (LH). Measure the resistance at front combination light assembly (LH) connector A-41.

1. Disconnect front combination light assembly (LH) connector A-41 and measure the resistance available at the wiring harness side of the connector.

2. Measure the resistance value between terminal 3 and ground.
- The resistance should equal 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 front combination light assembly (LH) connector A-41 (terminal 3) and ground.

Q: Is the wiring harness between front combination light assembly (LH) connector A-41 (terminal 3) and ground in good condition?

YES: Replace the headlight bulb (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 headlights illuminate normally.

STEP 6. Check the wiring harness between front combination light assembly (LH) connector A-41 (terminal 4) and front-ECU connector A-1OX (terminal 6).

Q: Is the wiring harness between front combination light assembly (LH) connector A-41 (terminal 4) and front-ECU connector A-1OX (terminal 6) in good condition?

YES: Replace the headlight bulb (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) illuminate normally.

STEP 7. Check front combination light assembly (RH) connector A-42 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is front combination light assembly (RH) connector A-42 in good condition?

YES: Go to Step 8.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. Verify that the headlight (LOW: RH) illuminate normally.

STEP 8. Check 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 headlight bulb (LOW: RH) normal?

YES: Go to Step 9.

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

STEP 9. Check the ground circuit to the headlight (RH). Measure the resistance at front combination light assembly (RH) connector A-42.

1. Disconnect front combination light assembly (RH) connector A-42 and measure the resistance available at the wiring harness side of the connector.

STEP 10. Check the wiring harness between front combination light assembly (RH) connector A-42 (terminal 3) and ground.

Q: Is the wiring harness between front combination light assembly (RH) connector A-42 (terminal 3) and ground in good condition?

YES: Replace the headlight bulb (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) illuminate normally.

STEP 11. Check the wiring harness between front combination light assembly (RH) connector A-42 (terminal 4) and front-ECU connector A-1 OX (terminal 6).

Q: Is the wiring harness between front combination light assembly (RH) connector A-42 (terminal 4) and front-ECU connector A-1 OX (terminal 6) in good condition?

YES: Replace the headlight bulb (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) illuminate normally.

STEP 12. Check headlight (LH) connector A-15 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are headlight (LH) connector A-15 in good condition?

YES: Go to Step 13.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. Verify that the headlight (HI: LH) illuminate normally.

STEP 13. Check headlight bulb (HI: LH).

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

Q: Is headlight bulb (HI: LH) normal?

YES: Go to Step 14.

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

STEP 14. Check the ground circuit to the headlight (LH). Measure the resistance at headlight (LH) connector A-15.

1. Disconnect headlight (LH) connector A-15 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 equal 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES: Go to Step 16.

NO: Go to Step 15.

STEP 15. Check the wiring harness between headlight (LH) connector A-15 (terminal 2) and ground.

Q: Is the wiring harness between headlight (LH) connector A-15 (terminal 2) and ground in good condition?

YES: Replace the headlight bulb (HI: LH). Verify that the headlight (HI: 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 (HI: LH) illuminate normally.

STEP 16. Check the wiring harness between headlight (LH) connector A-15 (terminal 1) and front-ECU connector A-1 OX (terminal 2).

Q: Is the wiring harness between headlight (LH) connector A-15 (terminal 1) and front-ECU connector A-1 OX (terminal 2) in good condition?

YES: Replace the headlight bulb (HI: LH). Verify that the headlight (HI: 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 (HI: LH) illuminate normally.

STEP 17. Check headlight (RH) connector A-21 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are headlight (RH) connector A-21 in good condition?

YES: Go to Step 18.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. Verify that the headlight (HI: LH) illuminate normally.

STEP 18. Check headlight bulb (HI: RH).

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

Q: Is headlight bulb (HI: RH) normal?

YES: Go to Step 19.

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

STEP 19. Check the ground circuit to the headlight (RH). Measure the resistance at headlight (RH) connector A-21.

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

STEP 20. Check the wiring harness between headlight (RH) connector A-21 (terminal 2) and ground.

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

YES: Replace the headlight bulb (HI: RH). Verify that the headlight (HI: 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 (HI: RH) illuminate normally.

STEP 21. Check the wiring harness between headlight (RH) connector A-21 (terminal 1) and front-ECU connector A-1 OX (terminal 2).

Q: Is the wiring harness between headlight (RH) connector A-21 (terminal 1) and front-ECU connector A-1 OX (terminal 2) in good condition?

YES: Replace the headlight bulb (HI: RH). Verify that the headlight (HI: 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 (HI: RH) illuminate normally.

STEP 22. Check combination meter connector C-01 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is combination meter connector C-01 in good condition?

YES: Go to Step 23.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. Verify that the high-beam indicator light illuminates normally.

STEP 23. Check high-beam indicator light bulb.

1. Remove the high-beam indicator light bulb.
2. Verify that the high-beam indicator light bulb is not damaged or burned out.

Q: Is the high-beam indicator light normal?

YES: Go to Step 24.

NO: Replace the bulb. Verify that the high-beam indicator light illuminates normally.

STEP 24. Check the combination meter (printed-circuit board).

1. Remove the combination meter. Refer to Combination Meter Assembly and Vehicle Speed Sensor.
2. Remove the high-beam indicator light bulb. Then measure the resistance value between the bulb terminals.
3. Install the bulb to the combination meter, and then measure the resistance value between connector C-01 terminals 4 and 5. The measured resistance value should be roughly the same as the value measured in Step 2.

Q: Are these two resistance values extremely different?

YES: Repair or replace the combination meter (printed circuit board). Verify that the headlight-beam indicator light illuminates normally.

NO: (roughly the same) : Go to Step 25.

STEP 25. Check the battery power supply circuit to the combination meter. Measure the resistance at combination meter connector C-01.

1. Disconnect combination meter connector C-01 and measure the resistance available at the wiring harness side of the connector.

2. Measure the resistance value between terminal 4 and ground.
- The resistance should equal 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES: Go to Step 27.

NO: Go to Step 26.

STEP 26. Check the wiring harness between combination meter connector C-01 (terminal 5) and ground.

Q: Is the wiring harness between combination meter connector C-01 (terminal 5) and the battery in good condition?

YES: Replace the combination meter. Verify that the high-beam indicator light 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 high-beam indicator light illuminates normally.

STEP 27. Check the wiring harness between combination meter connector C-01 (terminal 4) and front-ECU connector A-1 OX (terminal 2).

NOTE: Also check intermediate connector C-129 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-129 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Is the wiring harness between combination meter connector C-01 (terminal 4) and front-ECU connector A-1 OX (terminal 2) in good condition?

YES: Replace the combination meter. Verify that the high-beam indicator light 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 high-beam indicator light illuminates normally.