Inspection Procedure O-4

Hazard Warning Light Switch Input Circuit:

CIRCUIT OPERATION
The ETACS-ECU operates various functions according to the input signal from the hazard warning light switch.

TECHNICAL DESCRIPTION (COMMENT)
Hazard warning light switch input signal is used to operate the following device or system. If the signal fails, these device or system will not work normally.
- Hazard warning light
- Keyless entry system (Registering the encrypted code)

TROUBLESHOOTING HINTS
- Malfunction of the hazard warning 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 hazard warning light switch.
If the hazard warning light switch is damaged, repair it. The hazard warning light switch input signal should be able to be checked and the functions, which are described in
the "Technical Description (comment)," should work normally.
If the hazard warning light switch is in good condition, go to Step 2.




STEP 2. Check the hazard warning light switch ground circuit at the hazard warning light switch connector C-10.
1. Disconnect the hazard warning light switch connector C-10 and measure at the harness side.
2. Resistance between terminal 2 and ground.
- Should be less than 2 Ohms.
If open circuit, go to Step 3.
If less than 2 Ohms. go to Step 5.




STEP 3. Check the hazard warning light switch connector C-10 for damage.
If the hazard warning light switch connector C-10 is damaged, repair or replace it. Refer to Harness Connector Inspection.
The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.
If the connector is in good condition, go to Step 4.




STEP 4. Check the harness wire between hazard warning light switch connector C-10 and ground.
If the harness wire between hazard warning light switch connector C-10 and ground is damaged, repair it.
The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.







STEP 5. Check the hazard warning light switch connector C-10 and ETACS-ECU connector C-111 for damage.
If the hazard warning light switch connector C-10 and ETACS-ECU connector C-111 are damaged, repair or replace them. Refer to Harness Connector Inspection.
The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.
If the connectors are in good condition, go to Step 6.







STEP 6. Check the harness wire between hazard warning light switch connector C-10 and ETACS-ECU connector C-111.
If the harness wire between hazard warning light switch connector C-10 and ETACS-ECU connector C-111 is damaged, repair it.
The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.
If the harness wire are in good condition, replace the ETACS-ECU.
The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.