The system will need to go through a calibration procedure.

2. Run the engine to get it up to operating temperature.

3. Then run the blower on high speed and temperature at full hot. Run the vehicle for 3-5 minutes to warm the Heating Ventilation and Air Conditioning (HVAC) system.

4. Then do the following:
Set the blower motor to high speed.
Set the mode position to the Panel vents.
Set the temperature to Cold (both slide pots if equipped).
Depress WASH and REAR WIPER buttons simultaneously for 5 seconds [until all Light Emitting Diodes (LEDs) light].

5. What will happen:
All LEDs will turn on for 5 seconds.
Calibration test is running when REAR WIPER and INTERMITTENT are alternately flashing. Cooldown test is running if A/C and RECIRC are alternately flashing.
Calibration is complete when the REAR WIPER LED is the only LED flashing. Push the rear wiper button to exit the calibration procedure.

6. Note: In order to pass this test, the A/C system must be functional. Part of the calibration test is running the compressor clutch and monitoring the temperature drop in the evaporator via the evaporator temperature sensor.