Inspection Procedure 18: Air volume of rear blower cannot be changed

COMMENTS ON TROUBLE SYMPTOM

If the blower air volume can not be changed when the blower switch is operated, the wiring harness between A/C-ECU and rear heater controller, and rear power transistor circuit system may be defective.

PROBABLE CAUSES

Malfunction of rear power transistor
Malfunction of the A/C-ECU
Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Check whether the air conditioner sets a diagnosis code or not.

Q. Is the check result normal?

	Go to Step 2.

	Refer to diagnosis code chart .

STEP 2. M.U.T.-III actuator test

Carry out the actuator test. (Refer to

Item 04: Rear Blower fan: OFF
Item 05: Rear Blower fan: AUTO <vehicles with dual automatic A/C>
Item 06: Rear Blower fan: Lo
Item 07: Rear Blower fan: Middle
Item 08: Rear Blower fan: High

Q. Does the blower motor work normally?

	Go to Step 3.

	Go to Step 4.

STEP 3. M.U.T.-III data list

Check that the following service data display contents are normal. (Refer to

Item 22: Rear blower motor
Item 23: Rear blower motor (target value)
Item 32: Rear control OFF SW
Item 33: Rear control FAN SW

Q. Is the check result normal?

	Go to Step 10.

	Refer to Inspection Procedure 16: Rear blower does not work <Vehicle with rear heater or rear cooler> or Inspection Procedure 17: Rear blower does not work <Vehicle with dual automatic A/C> .

STEP 4. Connector check: D-11 rear power transistor connector

Q. Is the check result normal?

Go to Step 5.

Repair the connector.

STEP 5. Resistance measurement at D-11 rear power transistor connector.

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

(2)Continuity between terminal 2 and body earth.
OK: 2 ohm or less

Q. Is the check result normal?

Go to Step 7.

Go to Step 6.

STEP 6. Check the wiring harness between D-11 rear power transistor connector terminal No.2 and earth.

Check the rear window defogger earth line for open or short 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 or replace the wiring harness.

STEP 7. Connector check: C-104 A/C-ECU connector

Q. Is the check result normal?

Go to Step 8.

Repair the connector.

STEP 8. Check the wiring harness between D-11 rear power transistor connector (terminal 1 and 3) and C-104 A/C-ECU connector (terminal 60 and 59).

note

Prior to the wiring harness inspection, check intermediate connector C-15, and repair if necessary.

Check the rear window defogger relay line for open or short circuit.

Q. Is the check result normal?

Go to Step 9.

Repair the wiring harness.

STEP 9. Replace the rear power transistor and recheck the trouble symptom

Check that the rear blower motor should work normally.

Q. Is the check result normal?

	This diagnosis is complete.

	Replace the A/C-ECU.

STEP 10. 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.