Inspection Procedure 3: The blower air volume cannot be changed




COMMENTS ON TROUBLE SYMPTOM


If the blower air amount cannot be changed when the blower switch is operated, the blower switch may be defective.

TROUBLESHOOTING HINTS



DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-46 power transistor connector


Q. Is the check result normal?

Go to Step 2.

Repair the connector.

STEP 2. Check the wiring harness between C-201 blower motor connector terminal No.2 and C-46 power transistor connector terminal No.1.





  • Check the blower relay earth wires for open circuit.

Q. Is the check result normal?

Go to Step 3.

Repair the wiring harness.

STEP 3. Connector check: C-44 A/C-ECU connector


Q. Is the check result normal?

Go to Step 4.

Repair the connector.

STEP 4. Check the wiring harness between C-46 power transistor connector (terminals 1 and 3) and C-44 A/C-ECU connector (terminals 36 and 33).



  • Check the A/C-ECU input line for open circuit.

Q. Is the check result normal?

Go to Step 5.

Repair the wiring harness.

STEP 5. Resistance measurement at the C-46 power transistor connector.


(1)Disconnect the connector, and measure at the wiring harness side.

(2)Measure the resistance between terminal 2 and body earth.
OK: Continuity (Less than 2Ω)

Q. Is the check result normal?

Go to Step 7.

Go to Step 6.

STEP 6. Check the wiring harness between C-46 power transistor connector terminal No.2 and body earth.



  • Check the power transistor earth 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 7. Replace the power transistor, and then recheck the trouble symptom
Check that the blower motor works normally.

Q. Is the check result normal?
This diagnosis is complete.
Replace the A/C-ECU.