Inspection Procedure O-5

The fog light switch signal is not sent to the ETACS-ECU.

Fog Light Switch Input Circuit:

CIRCUIT OPERATION
The ETACS-ECU operates the fog lights according to the input signal from the fog light switch.

TECHNICAL DESCRIPTION (COMMENT)
The fog lights will not work normally if the fog light switch input signal is an error.

TROUBLESHOOTING HINTS
- Malfunction of the fog light switch
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991529: Diagnostic Trouble Code Check Harness







STEP 1. Check the fog light switch.

Q: Is the tog light switch in good condition?

YES: Go to Step 2.
NO: Repair it. The fog light switch input signal should be able to be checked and the fog lights should work normally.

STEP 2. Check the tog light switch ground circuit at the fog light switch connector C-139.
1. Disconnect the fog light switch connector C-139 and measure at the harness side.




2. Measure the resistance between terminal 7 and ground.

Q: Is the resistance less than 2 ohm?

YES: Go to Step 5.
NO: Go to Step 3.




STEP 3. Check fog light switch connector C-139 for damage.

Q: Is fog light switch connector C-139 in good condition?

YES: Go to Step 4.
NO: Repair or replace it. Refer to Harness Connector Inspection. The fog light switch input signal should be able to be checked and the fog light should work normally.




STEP 4. Check the harness wires between fog light switch connector C-139 and ground.

NOTE: After checking joint connector C-141, check the wires. If joint connector C-141 is damaged, repair or replace it. Refer to Harness Connector Inspection.

Q: Are the harness wires between fog light switch connector C139 and ground in good condition?

YES: There is no action to be taken.
NO: Repair them. The fog light switch input signal should be able to be checked and the fog lights should work normally.




STEP 5. Check fog light switch connector C-139 and ETACS-ECU connector C-313 for damage.

Q: Are fog light switch connector C-139 and ETACS-ECU connector C-313 in good condition?

YES: Go to Step 6.
NO: Repair or replace them. Refer to Harness Connector Inspection. The fog light switch input signal should be able to be checked and the fog lights should work normally.




STEP 6. Check the harness wire between fog light switch connector C-139 and ETACS-ECU connector C-313.

Q: Is the harness wire between fog light switch connector C-139 and ETACS-ECU connector C-313 in good condition?

YES: Replace the ETACS-ECU. The fog light switch input signal should be able to be checked and the fog lights should work normally.
NO: Repair it. The fog light switch input signal should be able to be checked and the fog lights should work normally.