Question about 2007 GMC Safari

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I have a 2004 M-Van with a 4.3 V-6. The heat, defrost, AC control seems to be stuck. No matter which position is selected, air comes out of all outlets equally. I suspect it is either a vacuum problem or the switch is fried.

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  • Anonymous Aug 23, 2008

    my '98 safari only sends air out the dash (defrost) vents and the vents at the feet of front and rear passenger seats



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I would say you are correct thinking its a vacuum problem. On my '98 Safari, I had the same problem and found a plastic vacuum line inside the engine compartment had touched something hot and melted a small hole in it. I was able to cut the bad part out of the vacuum line and splice it with a small piece of rubber hose whose inside diameter was just smaller than the ouside diameter of the vacuum line. It's been running for two years with no further problems.

Posted on Aug 30, 2008


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