Inspection Procedure 22: Rear fan switch system <LHD>

COMMENTS ON TROUBLE SYMPTOM
If a rear fan switch signal is not set to the A/C-ECU, the rear fan switch or the rear fan switch circuit system may be defective.

PROBABLE CAUSES

  • Malfunction of the rear fan switch
  • Malfunction of the A/C-ECU
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-19 rear fan switch

Q. Is the check result normal?

Go to Step 2.

Repair the connector.

STEP 2. Check the rear fan switch
Refer to .

Q. Is the check result normal?
Go to Step 3.
Replace the rear fan switch.

STEP 3. Voltage measurement at C-19 rear fan switch connector.

(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the ON position.

(3)Measure the voltage between terminal 1 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 5.

Go to Step 4.

STEP 4. Check the wiring harness between C-19 rear fan switch connector terminal No.1 and the ignition switch (IG2).


note Prior to the wiring harness inspection, check joint connector C-31 and junction block connector C-205 and C-202, and repair if necessary.

  • Check the rear fan switch power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

STEP 5. Connector check: C-104 A/C-ECU connector.

Q. Is the check result normal?

Go to Step 6.

Repair the connector.

STEP 6. Check the wiring harness between C-19 rear fan switch connector terminal No.2 and C-104 A/C-ECU connector terminal No.71.


  • Check the rear fan switch activating lines for open or short circuit.

Q. Is the check result normal?

Go to Step 7.

Repair the wiring harness.

STEP 7. Recheck the trouble symptom

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
Replace the A/C-ECU.