A/C Not Sufficiently Cooling (Calibrate HVAC Module/Verify Connection of Mode Switch C1 Connector and Temperature Cable)

Some customers may comment that the A/C is not cooling sufficiently.

Engineering has determined that the HVAC control module may need to be calibrated.

DO NOT REPLACE ANY HVAC COMPONENTS OR ATTEMPT TO DIAGNOSE THE SYSTEM PRIOR TO ENSURING THE HVAC CONTROL MODULE HAS BEEN CALIBRATED.

HVAC CONTROL MODULE CALIBRATION PROCEDURE:

1. With the ignition "ON", simultaneously press the "A/C" and "Recirc" buttons three times in a period of LESS than two seconds.
2. Verify that the "A/C" and "Recirc" LED's are flashing. Allow 15 seconds for the calibration to complete.
3. After the calibration is complete, press the "A/C" and "Recirc" buttons to verify the LED state changes.

Important: If the LED state does not change, inspect the following:

•	Inspect for full engagement of the HVAC control module C1 connector (refer to SI Document ID #1380878).

•	Inspect the connection of the temperature cable (SI Document ID #1243751).

4. Perform a system function test to confirm operation of the following functions:

•	Noticeable blower speed change should occur from speed settings 1 thru 4.

•	Press the "A/C" button. The temperature of the outlet air must drop and the A/C indicator must light.

•	Turn the temperature knob from cold to hot. An increase in temperature should be detected.

•	Press the "recirc" button and verify increase in blower noise and verify indicator lights.

If the HVAC control module calibration procedure does not resolve the customer's concern, follow published diagnostics found in SI.

For vehicles repaired under warranty, use: