F and A/C ON

DTC Troubleshooting: B1238 or Indicator F and A/C ON

DTC B1238 or DTC indicator F and A/C ON: A Problem in the Passenger's Air Mix Control Linkage, Door, or Motor Circuit

1. Clear the DTC with the HDS.

2. Turn the ignition switch to LOCK (0), and then to ON (II).

3. Do the self-diagnostic function with the HDS Initial Inspection and Diagnostic Overview or climate control unit. Initial Inspection and Diagnostic Overview

4. Check for DTCs.

Is DTC B1238 or F and A/C ON indicated?
YES - Go to step 5.

NO - Intermittent failure. Check for loose wires or poor connections on the passenger's air mix control motor circuit.


5. Turn the ignition switch to LOCK (0).

6. Test the passenger's air mix control motor. Passenger's Air Mix Control Motor Test

Is the passenger's air mix control motor OK?
YES - Go to step 7.

NO - Replace the passenger's air mix control motor, Passenger's Air Mix Control Motor Replacement or repair the passenger's air mix control linkage or door.


7. Disconnect the passenger's air mix control motor 7P connector.

8. Disconnect climate control unit connector A (28P).

9. Check for continuity between the following terminals of climate control unit connector A (28P) and the passenger's air mix control motor 7P connector.





Is there continuity?
YES - Go to step 10.

NO - Repair an open in the wire(s) between the climate control unit and the passenger's air mix control motor.






10. Check for continuity between body ground and climate control unit connector A (28P) terminals No. 1 and No. 2 individually.

Is there continuity?
YES - Repair a short to body ground in the wire(s) between the climate control unit and the passenger's air mix control motor.

NO - Substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.