Manufacturer Code Charts: 3

HVAC DTC Troubleshooting: 3

DTC indicator 3:

A Problem in the Air Mix Control Linkage, Door, or Motor Circuit

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

2. Do the self-diagnostic function with the HVAC control unit How To Troubleshoot The Heating And A/C Systems (Without Climate Control).

3. Check for DTCs.

Is DTC 3 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 to LOCK (0).

5. Test the air mix control motor Air Mix Control Motor Test (Without Climate Control).

Is the air mix control motor OK?

YES -

Go to step 6.

NO -

Replace the air mix control motor Air Mix Control Motor Replacement (Without Climate Control), or repair the air mix control linkage or door.�

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

7. Disconnect the HVAC control unit 28P connector.

8. Check for continuity between the following terminals of the HVAC control unit 28P connector and the air mix control motor 7P connector.









Is there continuity?

YES -

Go to step 9.

NO -

Repair an open in the wire(s) between the HVAC control unit and the air mix control motor.�

9. Check for continuity between body ground and the HVAC control unit 28P connector terminals No. 23 and No. 24 individually.





Is there continuity?

YES -

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

NO -

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).�