GM Service Manual Online
For 1990-2009 cars only

Important: Review the Air Delivery Description and Operation and the Air Temperature Description and Operation in order to familiarize yourself with the system functions.

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.
    • Inspect all related ground points for being clean and tight.

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:

    •  HVAC Compressor Clutch Does Not Engage
    •  HVAC Compressor Clutch Does Not Disengage
    •  Blower Motor Always On
    •  Blower Motor Inoperative
    •  Blower Motor Malfunction
    •  Air Delivery Improper
    •  Air Recirculation Malfunction

Refer to Symptoms - Engine Cooling for diagnosis of the electric cooling fan.

Refer to the following:

    •  Leak Testing
    •  Air Conditioning (A/C) System Performance Test
    •  TXV Air Conditioning (A/C) System Diagnosis
    •  Heating Performance Diagnostic
    •  Defrosting Insufficient
    •  Noise Diagnosis - Blower Motor
    •  Noise Diagnosis - Air Conditioning (A/C) System
    •  Odor Diagnosis