Question about 1999 GMC Sonoma

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Air floww only comes out the dash and not the floor

1999 Sonoma the air only flows out the dash and not at the floor

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  • hufflin May 23, 2009

    I went and checked, what is going on is when you turn the switch to floor to comes out the dash but not the floor in any position



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One of your a/c vacum lines is broken its from your intake manifold to a/c your hood and look towards the drivers side on the manifold from the middle you should see a 1/8 air line it runs towards the passenger front.

Posted on May 23, 2009

  • Danny May 24, 2009

    If you can turn and change the vents to dash and to the defrost mode and it changes from vent to vent and not the floor you will have a bad valve in the system or something is caught in it.which means that valve to the vent has a broken vacum line or its stuck like something could of got caught in there and not letting it open.This is a tuff job to figure out unless you can get a squematic on the system.Besides the fact that you would hav to remove the bottom part of your dash to get a good look at it.



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