13. Hazard Lights Do Not Work With Switch, Bulbs Are OK
CIRCUIT OPERATION
If the ETACS-ECU receives a signal from the hazard warning light switch, the flasher timer circuit (which is incorporated in the ETACS-ECU) makes the front and rear combination lights flash.
TECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU receives a signal from the hazard warning light switch. If the hazard warning light switch works normally, the turn-signal light switch or the harness may be faulty.
TROUBLESHOOTING HINTS
- Malfunction of the ETACS-ECU
- Malfunction of the hazard warning light switch
- Damaged harness wires or connectors
DIAGNOSIS
Required Special Tools:
MB991223: Harness set
MB991502: Scan Tool (MUT-II)
MB991529: Diagnostic Trouble Code Check Harness
CAUTION: To prevent damage to scan tool MB991502, make sure that the ignition switch is "OFF" before connecting or disconnecting the scan tool.
STEP 1. Check the input signal from the hazard warning light switch, using either the scan tool or a voltmeter.
- Using scan tool MB991502
1. Connect Scan Tool MB991502 to the data link connector.
2. Check that the tone alarm of the scan tool sounds when the hazard warning switch is on.
If the tone alarm of the scan tool does not sound, the input signal from the hazard warning light switch is not normal. Go to Step 2.
If the tone alarm of the scan tool sounds, the input signal from the hazard warning switch is normal. Replace the ETACS-ECU, and go to Step 9.
- Using a voltmeter
1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. If a voltmeter indicator deflects once when the hazard warning light switch is on, the ETACS-ECU input signal for that hazard warning switch is normal.
If the input signal of the hazard warning light switch is not normal, go to Step 2.
If the input signal of the hazard warning switch is normal, replace the ETACS-ECU, and go to Step 9.
STEP 2. Check the ETACS-ECU power supply (battery)
1. Measure voltage between ETACS-ECU connector C-86 terminal number 2 and ground.
- Voltage should be approximately 12 volts (battery positive voltage).
2. Measure voltage between ETACS-ECU connector C-86 terminal number 18 and ground.
- Voltage should be approximately 12 volts (battery positive voltage).
It approximately 12 volts, repair the ETACS-ECU. Check that the malfunction is eliminated.
If not approximately 12 volts, go to Step 3.
STEP 3. Check ETACS-ECU connector C~6 for damage.
If harness connector C-86 is damaged, repair or replace it. Refer to Harness Connector Inspection.
If harness connector C-86 is in good condition, go to Step 4.
STEP 4. Check the harness wires between ETACS-ECU connector C-86 and battery.
If any harness wires between ETACS-ECU C-86 and battery are damaged, repair them.
If the harness wires are in good condition, go to Step 5.
NOTE: After inspecting intermediate connector C-66 and junction block connectors C-78 and C-84, inspect the wire. If intermediate connector C-66 and junction block connector C-78 and C-84 are damaged, repair or replace them. Refer to Harness Connector Inspection.
STEP 5. Check the harness wire between ETACS-ECU C86 and body ground.
If any harness wires between ETACS-ECU connector C-86 and body ground are damaged, repair them. Check that the malfunction is eliminated. Then go to step 6.
NOTE: After inspecting the junction block connector C-73, inspect the wire. If junction block connector C-73 is damaged, repair or replace it. Refer to Harness Connector Inspection.
STEP 6. Check the hazard warning light switch.
1. Remove the hazard warning light switch.
2. Disconnect hazard warning light switch connector C-07 and check the hazard warning light switch for continuity.
If the hazard warning light switch is in good condition, go to Step 7.
If the hazard warning light switch is faulty, replace the hazard warning switch. Check that the malfunction is eliminated.
STEP 7. Check hazard warning switch connector C-07 for damage.
If harness connector C-07 is damaged, repair or replace it.
Refer to Harness Connector Inspection. If harness connector C-07 is in good condition, go to Step 8.
STEP 8. Check the harness wires between the hazard warning switch connector C-07 and ETACS-ECU C-82.
If any harness wires between hazard warning light switch connector C-07 and ETACS-ECU C-82 are damaged, repair them.
If the harness wires are in good condition, replace that the ETACS-ECU and go to Step 9.
STEP 9. Check symptoms.
Confirm that the hazard warning light switch operates normally.