GM Service Manual Online
For 1990-2009 cars only

Blower Noise

A constant air rush noise is typical of high speed blower operation. Some systems and modes are more noisy than other systems. If possible, verify the noise using a similar vehicle in order to determine if the noise is typical or excessive.

Vibration/Rattle

Important: Feel the lines, the hoses, and the brackets during the diagnosis. Many noises stop when you contact the component.

Potential causes include the following conditions:

    â€¢ The belt is not in proper alignment in the pulley groove.
    â€¢ The belt tensioner is faulty.
    â€¢ The lines or the hoses are in contact with each other.
    â€¢ The brackets are loose.
    â€¢ Other drive components are faulty.

Moans

Potential causes include the following conditions:

    â€¢ The air conditioning charge is not proper.
    â€¢ Other drive components are faulty.
    â€¢ A bracket is loose or is not in proper alignment.
    â€¢ The lines or the hoses are in contact with each other.

Screech

Potential causes include the following conditions:

    â€¢ The compressor bearings are faulty.
    â€¢ The compressor clutch is faulty.