GM Service Manual Online
For 1990-2009 cars only

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the HVAC System. Refer to Checking Aftermarket Accessories08.
    • Inspect the system components which are easily accessible or visible for obvious damage or for conditions which could cause the symptom.
    • The A/C compressor will not operate in cold, outside air temperatures. Refer to Manual HVAC Description and Operation.
    • The following conditions may cause window fogging:
       - A wet carpet
       - High humidity
       - An interior water leak
       - A blocked drain tube to the A/C evaporator
       - Maximum passenger capacity
       - Blocked body pressure relief valves
    • Inspect the air distribution system for causes of reduced airflow:
       - An obstructed or dirty passenger compartment air filter
       - Blocked or damaged air vents

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 one of the following symptom diagnostic procedures:

    •  Blower Motor Malfunction
    •  Leak Testing
    •  Defrosting Insufficient
    •  Noise Diagnosis - Blower Motor
    •  Noise Diagnosis - Air Conditioning (A/C) System
    •  Noise Diagnosis - HVAC Module
    •  Odor Diagnosis