Inspection Procedure K-2

Flasher timer: Hazard warning lights does not flash when the hazard warning light switch is turned on.

Turn-signal Light Drive Circuit
Refer to Inspection Procedure K-1.

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 turn-signal lights flash.

TECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU makes the turn-signal lights flash, based on the input signals from the hazard warning light switch. If the turn-signal lights do not flash normally, the hazard warning light switch input circuit or the ETACS-ECU may be defective.

If the turn-signal lights do not flash, a defect in the ETACS-ECU power supply line specific to the turn signal lights is suspected.

NOTE: If only one of the turn-signal lights does not flash, the light bulb may be burned out or the harness wires between the ETACS-ECU and the light may be defective. In this case, check the circuit by referring to Turn-signal Light and Hazard Warning Light.

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 turn-signal light operation.

Q: Do the turn-signal lights work normally?

YES: Go to Step 2 or 3 .
NO: Solve the problem first. Refer to Inspection Procedure K-1.

STEP 2. Check the input signal (by using scan tool MB991502).
Check the input signals from the hazard warning light switch.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Check that the tone alarm of scan tool MB991502 sounds when the input signal enters.

Q: Does the tone alarm of scan tool MB991502 sound when the input signal enters?

YES: Replace the ETACS-ECU. The hazard warning lights should flash normally.
NO: Check the hazard warning light switch input circuit. Refer to Inspection Procedure O-4.

STEP 3. Check the input signal (by using a voltmeter).
Check the input signals from the hazard warning light switch.

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. Check that the voltmeter indicator deflects once when the input signal enters.

Q: Does the voltmeter indicator deflect?

YES: Replace the ETACS-ECU. The hazard warning lights should flash normally.
NO: Check the hazard warning light switch input circuit. Refer to Inspection Procedure O-4.