All the HVAC control module diagnostic trouble codes (DTC) are displayed with a blink code on the A/C, recirculation and rear defrost LED's. The DTC will flash after diagnostic mode is entered. If there is no DTC present all of the LED's will flash quickly. If a DTC is present, the rate at which the LED will flash will be slower than the quick flash associated with no DTC. The LED will flash 8 times then repeat this until the code is cleared or ignition is turned OFF. To enter diagnostic mode perform the following procedure:
- Turn Off the ignition.
- Press and hold the following HVAC control module switches:
- While pressing the switches, turn the ignition to the Run position.
- Wait 5 seconds.
- Observe the switch LED's.
- The LED's will flash quickly if there is no DTC's are present.
- If 1 of the LED's flash 8 times then there is an HVAC control module DTC. Refer to the following table to determine DTC:
| • | A/C request switch |
| • | Recirculation switch |
| • | Rear defrost switch |
DTC | Flashing Switch LED | Code Description |
|---|---|---|
001 | Rear Defrost Switch | Mode Actuator Failure |
010 | Recirculation Switch | HVAC Control Module Failure |
100 | A/C Request Switch | Air Temperature Actuator Failure |
There is only one DTC for each of the HVAC control module switch LED's. If there is only 1 DTC that LED will flash 8 times slowly while the other LED will flash quickly to indicate no DTC. If multiple DTC are set they will flash 8 times slowly.
Refer to Symptoms - HVAC Systems - Manual if a DTC is present. To exit diagnostic mode turn the ignition to the OFF position.
