Heating and Air Conditioning

DTC B1233 or DTC indicator 1: An Open in the Air Mix Control Motor Circuit

1. Clear the DTC with the HDS.
2. Operate the heater-A/C control system in several modes.
3. Check for DTCs using the HDS or self-diagnostic.

Is DTC B1233 or 1 indicated?

YES - Go to step 4.

NO - Intermittent failure, check for loose wires or poor connections on the air mix control motor circuit.

4. Turn the ignition switch OFF.
5. Test the air mix control motor.

Is the air mix control motor OK?

YES - Go to step 6.

NO - Replace the air mix control motor.

6. Disconnect the air mix control motor 7P connector.
7. Disconnect the HVAC control unit 30P connector.




8. Check for continuity between the following terminals of the HVAC control unit 30P connector and the air mix control motor 7P connector.

Is there continuity?

YES - Check for loose wires or poor connections at the HVAC control unit 30P connector and at the air mix control motor 7P connector. If the connections are good, substitute a known-good HVAC control unit and recheck. If the symptom/indication goes away, replace the original HVAC control unit

NO - Repair any open in the wire(s) between the HVAC control unit and the air mix control motor.