QuestionQUESTION: I have a 2004 Chevrolet Avalanche I have had for the past year. Recently a problem with the air condition (a/c)developed. It was going off and on. This is bad especially in Arizona. However, the Chevy dealership advised me that the previous owner did some after after market work to the a/c, including placing a different control head in backwards. Because of that warranty is voided. What exactly does the control head do and what parts would be required to fix the problem? I appreciate any information that can be provided. Thanks.
ANSWER: Chuck,
The problem needs a bit of clarification: the A/C Control Head blinking on/off, the blower, or the compressor? Since you mention the Control Head problem, I'll assume that you meant the first.
The A/C Control Head (also referred to as a module in this vehicle) is the electronic interface, with buttons and knobs, to control all aspects of the climate control system. It contains logic to operate actuators. reads incoming data from various sensors, and communicates with the Body Control Module (necessary for all body functions). Quite simply, it's the climate control computer. To replace it, you just replace the unit in the dash (with the buttons and dials). Often, the logic can be updated with software revisions to fix known concerns or update new features -- although, with this concern, that's most likely a non-issue.
Is the Control Head currently in the vehicle a GM one? If so, I'm saddened at the lack of customer service with dealers these days. First, I don't understand how its possible to install one backwards(?) Regardless, I would have a nice chat with the Service Manager (NOT the writer), and calmly and truthfully explain your situation. Dealers have a *lot* of say in what is covered and what isn't -- often referred to as Goodwill. You might even try another dealer, and explain the situation ahead of time. Being second owner diminishes your bargaining power a bit, but they should still listen.
Still, if you don't want the hassle, and the Control Head blinks on and off, you could replace it yourself -- providing the power and grounds have been checked. Since it is tied in with the car's communication network, there is a very slight chance it's affected another device on the bus, but that's stepping ahead too much right now. There has been issues with these Control Heads in the past, particularly since they are an electro-mechanical device (pushing buttons and twisting dials) -- but more importantly, they are electronic, and susceptible to heat (like in Arizona).
Good luck!
---------- FOLLOW-UP ----------
QUESTION: Thank you for the information. Could itbe the blower or the compression The a/c comes on, then off. After while it comes on for an hour then goes off. Again, thanks for the information.
AnswerAgain, I ask...
1) Does the blower shut off (no air), OR
2) Does the air coming out of the vents turn warm, OR
3) Does the A/C Control Head display blink on and off?
One of the three. If it's the first one, chances are its a Blower Control Module issue. If it's warm air out the vents, and the compressor is off, then it may be a low refrigerant condition or an intermittent electrical issue. If it's the third thing, I've covered that in my previous post.
Have a good day!
