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John, GMC Technician
Category: GM
Satisfied Customers: 9176
Experience:  ASE MASTER TECHNICIAN/40 years experience
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1999 GMC: climate control..all switches and relays also brain ecm

Customer Question

I have 1999 GMC Jimmy With climate control it works intermitely some time works fine have replaced all switches and relays also brain ecm thermstatic switchs pressure
Submitted: 7 years ago.
Category: GM
Expert:  John replied 7 years ago.


Can you explain your problem in detail,exactly what does not work,when it does not work,& approx. how often this occurs ?


Any symptoms that occur along with this problem might be helpful.

Customer: replied 7 years ago.
It Happens intermitly push a/c button it flashes 3 times and compressor doesnt come on sometimes when driving it will decide to come on when it does it might work for 10 min or sometimres work for a day or 2
Expert:  John replied 7 years ago.
Your automatic climate control system is also controlled by other computers in your vehicle(BCM,PCM).All of these circuits,sensors,computers,& actuators have to communicate for proper operation.The first thing that should be done is to scan all (especially BCM) vehicle computers.The flashing button lights is a sign that circuit failure has occurred .This has to be diagnosed with a scan tool for clearing the failure & viewing data parameters of the system.

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