Inspection Procedure 11: The rear window defogger switch signal is not received. <vehicles with cooler>


caution Whenever the ECU is replaced, ensure that the input signal circuit is normal.

COMMENTS ON TROUBLE SYMPTOM


Input signal from the rear window defogger switch is used to operate the functions below. If the signal is abnormal, these functions will not work normally.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE


STEP 1. Check the rear window defogger switch.


Refer to .

Q. Is the check result normal?

Go to Step 2.

Replace the heater control panel (Refer to GROUP 55A - Heater Control Unit ).

STEP 2. Resistance measurement at heater control panel connector (earth terminal)


(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the heater control panel connector (earth terminal) and body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 4.

Go to Step 3.

STEP 3. Check of open circuit in earth line between heater control panel connector and body earth


Q. Is the check result normal?

Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).

Repair the connector(s) or wiring harness.

STEP 4. Check of short to power supply, short to earth, and open circuit in DFSW line between ETACS-ECU connector and heater control panel connector


Q. Is the check result normal?

Go to Step 5.

Repair the connector(s) or wiring harness.

STEP 5. M.U.T.-III data list


Check the input signals from the rear window defogger switch

Item No.
 Item name
 Normal condition
103
 Rear defogger switch
 OFF to ON (only when switch is operated)
OK: Normal condition is displayed.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).

Replace the ETACS-ECU (Refer to ).