Open or Short in the Mode Control Motor Circuit (Front)

DTC Troubleshooting: B1239 (3)

DTC B1239 or DTC indicator 3:

An Open or Short in the Mode Control Motor Circuit (Front)

1. Clear the DTCs with the HDS.

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

3. Do the Self-Diagnostic Function with the HDS or the HVAC control unit.

4. Check for DTCs.

Is DTC B1239 or 3 indicated?

YES -

Go to step 5.

NO -

Intermittent failure. Check for loose wires or poor connections on the front mode control motor circuit.

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

6. Test the front mode control motor Front Mode Control Motor Test.

Is the front mode control motor OK?

YES -

Go to step 7.

NO -

Replace the front mode control motor Front Mode Control Motor Replacement.

7. Disconnect the front mode control motor 7P connector.

8. Disconnect the HVAC control unit 28P connector.

9. Check for continuity between the following terminals of the HVAC control unit 28P connector and the front mode control motor 7P connector.













Is there continuity?

YES -

Go to step 10.

NO -

Repair an open in the wire(s) between the HVAC control unit and the front mode control motor.

10. Check for continuity between body ground and HVAC control unit 28P connector terminals No. 18, No. 19, No. 20, and No. 21 individually.





Is there continuity?

YES -

Repair a short to body ground in the wire(s) between the HVAC control unit and the front mode control motor.

NO -

Go to step 11.

11. Check for continuity between the HVAC control unit 28P connector terminals as follows.





Is there continuity between any of the terminals?

YES -

Repair a short in the wires between the HVAC control unit and the front mode control motor.

NO -

Go to step 12.

12. Turn the ignition switch to ON (II), and measure the voltage between body ground and HVAC control unit 28P connector terminals No. 18, No. 19, No. 20, and No. 21 individually.





Is there any voltage?

YES -

Repair a short to power in the wire(s) between the HVAC control unit and the front mode control motor. This short may also damage the HVAC control unit. Repair a short to power before replacing the HVAC control unit.

NO -

Check for loose wires or poor connections at the HVAC control unit 28P connector and at the front mode 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 HVAC Control Unit Removal/Installation (Without Climate Control).