Inspection Procedure 8

INSPECTION PROCEDURE 8: Outside/Inside Air Change over is not possible

Outside/Inside Air Selection Damper Control Motor Circuit:

CIRCUIT OPERATION
If the outside/inside air selection damper control motor does not operate normally, the outside/inside air selection damper control motor system may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the outside/inside air 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 (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A

STEP 1. Using scan tool MB991958, read the diagnostic trouble code.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

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 check result satisfactory?

YES: Refer to Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions

NO: Go to Step 2.

STEP 2. Using scan tool MB991958, check actuator test.

1. Connect scan tool MB991958 to the data link connector.
2. Start the engine.
3. Use scan tool MB991958 to run the actuator test.
- Item 13: Outside/inside air selection damper control motor: Outside air
- Item 14: Outside/inside air selection damper control motor: Inside air
- Check that the blower motor operates.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Does the blower motor operate normally?

YES: Replace the A/C-ECU.

NO: Go to Step 3.

STEP 3. Measure the voltage at outside/inside air selection damper control motor connector C-108.




1. Disconnect outside/inside air selection damper control motor connector C-108, and measure the voltage at the harness side.
2. Turn the ignition switch to the "ON" position.




3. Measure the voltage between terminal 7 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).

Q: Does the measured voltage correspond with this range?

YES: Go to Step 6.

NO: Go to Step 5.




STEP 4. Check outside/inside air selection damper control motor connector C-108 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is outside/inside air selection damper control motor connector C-108 in good condition?

YES: Go to Step 6.

NO: Repair or replace the connector. Check that the outside/inside air selection damper control motor works normally.










STEP 5. Check the wiring harness between outside/inside air selection damper control motor connector C-108 (terminal 7) and the ignition switch (IG2).

NOTE: Also check intermediate connector C-30, junction block connectors C-203 and C-205 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-30, junction block connector C-203 or C-205 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between outside/inside air selection damper control motor connector C-108 (terminal 7) and the ignition switch (IG2) in good condition?

YES: It can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points- How to Cope with Intermittent Malfunctions.

NO: Repair the wiring harness. Check that the outside/inside air selection damper control motor works normally.

STEP 6. Check the outside/inside air selection damper control motor.

Refer to Resistor, blower motor and inside/outside air selection damper control motor in Heating and Air Conditioning.

Q: Does outside/inside air selection damper control motor work normally?

YES: Go to Step 7.

NO: Replace the outside/inside air selection damper control motor. Check that the outside/inside air selection damper control motor works normally.




STEP 7. Check A/C-ECU connector C-26 and outside/inside air selection damper control motor connector C-108 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are A/C-ECU connector C-26 and outside/inside air selection damper control motor connector C-108 in good condition?

YES: Go to Step 8.

NO: Repair or replace the connector. Check that the outside/inside air selection damper control motor works normally.




STEP 8. Check the wiring harness between A/C-ECU C-26 (terminals 23 and 26) and outside/inside air selection damper control motor connector C-108 (terminals 6 and 4)

Also check intermediate connector C-30 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-30 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Are the wiring harness between A/C-ECU C-26 (terminals 23 and 26) and outside/inside air selection damper control motor connector C-108 (terminals 6 and 4) in good condition?

YES: Replace the A/C-ECU.

NO: Repair the wiring harness. Check that the outside/inside air selection damper control motor works normally.