GM Service Manual Online
For 1990-2009 cars only

Important: Review the system operation in order to familiarize yourself with the system functions.

Refer to Air Temperature Description and Operation .

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the system. Refer to Checking Aftermarket Accessories .
    • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

    •  Air Delivery Improper
    •  Air Recirculation Malfunction
    •  Blower Motor Inoperative
    •  Control Head Illumination/Display Does Not Operate Properly
    •  Control Head Inoperative
    •  HVAC Compressor Clutch Does Not Engage
    •  Too Cold in Vehicle
    •  Too Hot in Vehicle