Inspection Procedure 12: ETACS-ECU does not receive any signal from the hazard warning light switch.: Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe

1. STEP 1. Check center panel unit connector C-104 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is center panel unit connector C-104 in good condition? 

   YES:  Go to Step 2.

   NO:  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Check that the input signal of hazard warning light switch is normal.

2. STEP 2. Check the hazard warning light switch. 

   Remove the center panel unit. Then check continuity between the switch terminal and switch body.

   TESTER CONNECTION SPECIFIED CONDITION CHART
   
   

   Switch position	Tester connection	Specified condition
   Released	5 - switch body	Less than 2 ohms
   Pressed	5 - switch body	Open circuit

   Q: Is the hazard warning light switch in good condition? 

   YES:  Go to Step 3.

   NO:  Replace the center panel unit. Check that the input signal of hazard warning light switch is normal.

3. STEP 3. Check ETACS-ECU connector C-301 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ETACS-ECU connector C-301 in good condition? 

   YES:  Go to Step 4.

   NO:  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Check that the input signal of hazard warning light switch is normal.

4. STEP 4. Check the wiring harness between center panel unit connector C-104 (terminal 5) and ETACS-ECU connector C-301 (terminal 19). 

   Check the input lines for open circuit and short circuit.

   Q: Is the wiring harness between center panel unit connector C-104 (terminal 5) and ETACS-ECU connector C-301 (terminal 19) in good condition? 

   YES:  Replace the ETACS-ECU. Check that the input signal of hazard warning light switch is normal.

   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. Check that the input signal of hazard warning light switch is normal.