Heating/Air Conditioning
DTC indicator 3: A Problem in the Air Mix Control Linkage, Door, or Motor1. Clear the DTC .
2. Turn the ignition switch, to LOCK (0), and then turn to ON (II).
3. Do the self-diagnostic with the HVAC control unit.
4. Check for DTCs.
Is DTC 3 indicated?
YES - Go to step 5.
NO - Intermittent failure.
5. Turn the ignition switch to LOCK (0).
6. Test the air mix control motor.
Is the air mix control motor OK?
YES - Go to step 7.
NO - Replace the air mix control motor, or repair the air mix control linkage or door.
7. Check for continuity between the following terminals of the HVAC control unit 24P connector and the air mix control motor 7P connector.
Is there continuity?
YES - Go to step 8.
NO - Repair open in the wires between the HVAC control unit and the air mix control motor.
8. Check for continuity between body ground and the heater control panel 24P connector No. 19 and No. 20 terminals individually.
Is there continuity?
YES - Repair short to body ground in the wires 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.