Inspection Procedure I-5

I-5: Headlight, Taillight: High-Beam Indicator Light Does Not Illuminate.

High-beam Indicator Light Circuit:

Connectors:

CIRCUIT OPERATION
When the passing switch is on or the front-ECU is illuminating the headlights (high-beam), the ETACS-ECU illuminates the high-beam indicator light.

TECHNICAL DESCRIPTION (COMMENT)
If the headlights (high-beam and passing) operate normally, the combination meter (high-beam indicator light bulb or printed-circuit board), the front-ECU or the ETACS-ECU is suspected to be defective.

TROUBLESHOOTING HINTS
- Malfunction of the combination meter (high-beam indicator light bulb or printed-circuit board)
- Malfunction of the front-ECU
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tool:
- MB991223: Test Harness Set

STEP 1. Check the headlights (high-beam and passing) operation.
Q: Do the headlights (high-beam and passing) illuminate normally?

YES: Go to Step 2.

NO: Solve the problem first.




STEP 2. Check the high-beam indicator light circuit at the ETACS-ECU connector C-82.
1. Disconnect the ETACS-ECU connector C-82 and measure at the harness side.
2. Connect terminal 53 to the ground.

Q: Does the high-beam indicator light Illuminate?

YES: Go to Step 10.

NO: Go to Step 3.




STEP 3. Check the high-beam indicator light bulb.
Q: Is the high-beam indicator light bulb in good condition?

YES: Go to Step 4.

NO: Replace it. The high-beam indicator light should work normally.




STEP 4. Check the combination meter (printed-circuit board).
1. Remove the combination meter.
2. Remove the high-beam indicator light bulb. Then measure the resistance between the bulb terminals.
3. Install the bulb to the combination meter, and then measure the resistance between connector C-29 terminal 22 and 23. The resistance reading at this time should be much the same as the resistance measured at Step (2).

Q: Are the two resistance values extremely different each other?

YES: Repair or replace the combination meter (printed circuit board). The high-beam indicator light should work normally.

NO (much the same): Go to Step 5.

STEP 5. Check the combination meter power supply circuit at the combination meter connector C-29.
1. Disconnect the combination meter connector C-29 and measure at the harness side.




2. Measure the voltage between terminal 23 and ground.

Q: Is the voltage approximately 12 volts (battery positive voltage)?

YES: Go to Step 8.

NO: Go to Step 6.




STEP 6. Check combination meter connector C-29 for damage.
Q: Is combination meter connector C-29 in good condition?

YES: Go to Step 7.

NO: Repair or replace it. Refer to Harness Connector Inspection. The high-beam indicator light should work normally.
















STEP 7. Check the harness wires between combination meter connector C-29 and fusible link (1).

NOTE: After checking junction block connectors C-78 and C-85 and intermediate connector C-66, check the wires. If junction block connectors C-78 and C-85 and intermediate connector C-66 are damaged, repair or replace them. Refer to Harness Connector Inspection.

Q: Are the harness wires between combination meter connector C-29 and fusible link (1) in good condition?

YES: There is no action to be taken.

NO: Repair or replace them. The high-beam indicator light should work normally.







STEP 8. Check combination meter connector C-29 and ETACS-ECU connector C-82 for damage.
Q: Are combination meter connector C-29 and ETACS-ECU connector C-82 in good condition?

YES: Go to Step 9.

NO: Repair or replace them. Refer to Harness Connector Inspection. The high-beam indicator light should work normally.







STEP 9. Check the harness wire between combination meter connector C-29 and ETACS-ECU connector C-82.
Q: Is the harness wire between combination meter connector C-29 and ETACS-ECU connector C-82 in good condition?

YES: There is no action to be taken.

NO: Repair it. The high-beam indicator light should work normally.

STEP 10. Replacement of ECU.
1. Replace the ETACS-ECU.
2. The high-beam indicator light should work normally.

Q: Is the high-beam indicator light working normally?

YES: There is no action to be taken.

NO: Replace the front-ECU. The high-beam indicator light should work normally.