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2005 GMC Safari Question: no heat or a/c blows from the front vents



sherre, San Jose, CA, October 15, 2009, 20:15

when i use my a/c or heat it will come out from the window vent and from the back vents but will not come when i put to blow on me useing front vents and it will not blow on the feet area just keeping blowing from the window vent and the back vents in the van

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  • Medium-star Best Answer
    October 16, 2009, 12:25

    The a/c mode switching on your 2005 GMC Safari van is operated using engine vacuum. With no vacuum the system will default to the defrost mode. The most common cause for loss of vacuum to the a/c control is a damaged vacuum hose under the hood. Your van does not give much access to inspect the vacuum hoses but it must be done. Look carefully for broken or damaged vacuum hoses. There is a vacuum tank near the right front fender which stores vacuum for the a/c system - follow the hoses to and from that vacuum tank.

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    sherre, October 16, 2009, 19:28

    thank you for your help but does this all so includes the heat not blowing in the front vents also it just keeps blowing from the defrost also no matter which area i pick for the heat to blow also

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  • Answer #2

    Visitor, July 16, 2010, 13:20

    There were a lot of great tips here on the vacuum situation, so I'm adding mine.

    I replaced all the vacuum lines except the little skinny one leading across the top of the engine from the passenger side. That one had snapped and was brittle, but I could not reach the other end back in the engine compartment. I didn't have the time to remove the doghouse, so here is what I did:

    I had left over standard vacuum hose from doing the other replacements (about 10").
    I had some high temp silicone gasket sealer from Permatex.

    I removed as much of the brittle line as I felt I could and then smeared the gasket sealer for about 3 inches along the length of the remaining small tubing. I then slipped the standard vacuum line over both ends. Once done, I used a Q tip with a blob of silicone to dab on each end of the standard tubing.

    Voila! Sealed.

    I then loosely pinched some aluminum foil around the whole thing as a heat guard and put everything back together.

    Works fine.

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