Inspection Procedure 7

INSPECTION PROCEDURE 7: A/C Outlet Air Temperature does not Increase










CIRCUIT OPERATION

If the air outlet temperature cannot be adjusted, the air mixing damper control motor circuit may be failed.

TROUBLESHOOTING HINTS

- Malfunction of the air mixing damper control motor
- Malfunction of the A/C-ECU
- Damaged wiring harness or connectors

DIAGNOSIS

STEP 1. Using scan tool MB991958, check for diagnostic trouble code.

Check if an A/C-ECU DTC is set.

(1)Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."

(2)Turn the ignition switch to the "ON" position.

(3)Check if the DTC is set.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Refer to DIAGNOSTIC TROUBLE CODE CHART Symptom Chart.
NO Go to Step 2.
STEP 2. Check air mixing damper control motor connector C-214 and A/C-ECU connector C-209 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Are air mixing damper control motor connector C-214 and A/C-ECU connector C-209 in good condition?

YES Go to Step 3.
NO Repair or replace the connector. Harness Connector Inspection. Check that the A/C works normally.
STEP 3. Check the wiring harness between A/C-ECU connector C-209 (terminals 29, 35, 36, 34 and 28) and air mixing damper control motor connector C-214 (terminals 3, 2, 5, 4 and 1).

- Check the A/C-ECU signal line for open and short circuit.

Q. Are the wiring harness between A/C-ECU connector C-209 (terminals 29, 35, 36, 34 and 28) and air mixing damper control motor connector C-214 (terminals 3, 2, 5, 4 and 1) in good condition?

YES Go to Step 4.
NO Repair the wiring harness. Check that the A/C works normally.
STEP 4. Replace the air mixing damper control motor and check the trouble symptom again

Check the trouble symptom again.

Q. Is the check result satisfactory?

YES The procedure is complete.
NO Replace the A/C-ECU.