Inspection Procedure J-5

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 headlight (high-beam and passing) operation.
If the headlights (high-beam and passing) do not illuminate normally, solve the problem first.
If the headlights (high-beam and passing) illuminate normally, go to Step 2.




STEP 2. Check the high-beam indicator light circuit at the ETACS-ECU connector C-111.
1. Disconnect the ETACS-ECU connector C-111 and measure at the harness side.
2. Connect between terminal 53 and ground.
- The high-beam indicator light should illuminate.
If the high-beam indicator light does not illuminate, go to Step 3.
If the high-beam indicator light illuminate, replace the ETACS-ECU.
The high-beam indicator light should illuminate.




STEP 3. Check the high-beam indicator light bulb.
If the high-beam indicator light bulb has blown, replace it.
The high-beam indicator light should illuminate.
If the high-beam indicator light bulb is in good condition, go to Step 4.




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-42 terminals 21 and 22. The resistance reading at this time should be much the same as the resistance measured at Step (2).
If the two resistance values are extremely different each other, repair or replace the combination meter (printed-circuit board).
The high-beam indicator light should illuminate.
If the two resistance values are much the same, go to Step 5.







STEP 5. Check the combination meter connector C-42 and ETACS-ECU connector C-111 for damage.
If the combination meter connector C-42 and ETACS-ECU connector C-111 are damaged, repair or replace them. Refer to Harness Connector Inspection. The high-beam indicator light should illuminate.
If the connectors are in good condition, go to Step 6.







STEP 6. Check the harness wire between combination meter connector C-42 and ETACS-ECU connector C-111.
If the harness wire between combination meter connector C-42 and ETACS-ECU connector C-111 is damaged, repair it.
The high-beam indicator light should illuminate.
If the harness wire is in good condition, go to Step 7.
















STEP 7. Check the harness wires between combination meter connector C-42 and fusible link (2).

NOTE: After checking junction block connector C-104 and C-110 and intermediate connector C-89, check the wires. If junction block connector C-104 and C-110 and intermediate connector C-89 are damaged, repair or replace them. Refer to Harness Connector Inspection.

If the harness wires between combination meter connector C-42 and fusible link (2) are damaged, repair them.
The high-beam indicator light should illuminate.
If the harness wires are in good condition, replace the ETACS-ECU or front-ECU.
The high-beam indicator light should illuminate.