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  1. #1

    Default Newbie: 93 GMC Suburban Heater/AC control is not working.

    Hey whats going on guys,

    I have a problem, currently I'm driving a 93 GMC Suburban with No Heat. The control unit itself is not getting power, I've check the fuse under the dash and tried replacing the unit itself and still no success. I stay in Chicago where its 9 degree outside today and cant afford to put my truck in the shop due to work schedule and time.
    I have done a search through the forum for the answer and havent come up with anything (maybe I didnt look hard enough but its freezing here). If anyone can help me with an wiring diagram or has ever experience this issue and can direct me in the right path it would be GRATELY appreciated...


  2. #2


    Check to see if power is coming to the control head. If there is, then it has to be a bad or loose ground wire. If I remember correctly there is two wires that should have power going to the control head. One constant supply and one that comes on with the ignition. If they both have power, then it has to be the ground wire.Try removing the control head and moving the wires around while the ignition is on, if it comes on and off then you know there is a break in the wiring. Trace it down and repair.

  3. #3

    Join Date
    Feb 2008
    Red Wing, Minnesota, United States


    Check the blower motor relay, these tend to go and then you will have nothing. It sits in the footwell of the passanger side. Just take off the lower black plastic piece that is protecting the blower itself. It will be attached by a couple screws and will look like a little rats nest of hard preformed wires and most likely will be corroded.
    99 K1500 Suburban LT "THE BEAST"
    Hypertech III, K&N, true dual

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