HVAC

HVAC DTC Troubleshooting: 8

DTC 8:

A Short in the Air Mix Control Motor Circuit

1. Turn the ignition switch to LOCK (0), and then turn it to ON (II).

2. Do the Self-Diagnostic Function with the heater control panel Initial Inspection and Diagnostic Overview.

3. Check for DTCs.

Is DTC 8 indicated?

YES -

Go to step 4.

NO -

Intermittent failure. Check for damaged wires or poor connections in the air mix control motor circuit.�

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

5. Disconnect the air mix control motor 7P connector.

6. Disconnect the heater control panel 30P connector.

7. Check for continuity between body ground and heater control panel 30P connector terminals No. 11, No. 13, and No. 14 individually.





Is there continuity?

YES -

Repair a short to body ground in the wire(s) between the heater control panel and the air mix control motor.�

NO -

Go to step 8.

8. Turn the ignition switch to ON (II), and measure the same terminals for voltage between each terminal and body ground.





Is there any voltage?

YES -

Repair a short to power in the wire(s) between the heater control panel and the air mix control motor. This short also may damage the heater control panel. Repair a short to power before replacing the heater control panel.�

NO -

Go to step 9.

9. Substitute a known-good air mix control motor and recheck.

Did the symptom/indication go away?

YES -

The original air mix control motor is faulty, replace it Air Mix Control Motor Replacement.�

NO -

Substitute a known-good heater control panel, and recheck. If the symptom/indication goes away, replace the original heater control panel Service and Repair.�