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heater

  1. General GM Discussions
    Wassup I got a 2004 gmc sierra 1500 5.3 when I'm using the ac all speeds work fine heater and ac works fine but when I turn it down to 0 and go on freeway air starts to blow thru the vents not ac or hot just air like I left it on speeds 1-3 completely turns off fine when truck is turned off also...
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