Inspection Procedure 8

INSPECTION PROCEDURE 8: Air Outlet Vent Cannot Be Changed.

Mode Selection Damper Control Motor Circuit:

CIRCUIT OPERATION
If the air outlet cannot be switched, the mode selection damper control motor circuit may be failed.

TROUBLESHOOTING HINTS
- Malfunction of the mode selection damper control motor
- Malfunction of the A/C-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

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 to the data link connector
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. Diagnostic Trouble Code Descriptions

NO : Go to Step 2.

STEP 2. Check mode selection damper control motor connector C-112 and A/C-ECU connector C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are mode selection damper control motor connector C-112 and A/C-ECU connector C-20 in good condition?

YES : Go to Step 3.

NO : Repair or replace the connector. Check that the A/C works normally.

STEP 3. Check the wiring harness between A/C-ECU connector C-20 (terminal 29, 31, 32, 30 and 33) and mode selection damper control motor connector C-112 (terminals 3, 2, 5, 4 and 1).

- Check the AC-ECU signal line for open and short circuit.

Q: Are the wiring harness between A/C-ECU connector C-20 (terminal 29, 31, 32, 30 and 33) and mode selection damper control motor connector C-112 (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 mode selection 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.