Question about 1994 Pontiac Grand Prix

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1994 Grand Prix Air blows thru defrost and feet, not middle vents

Air Conditioner blows cold but only goes thru the defrost and the feet. Barely anything goes thru the main vents.

Last year it did but would go to the defrost when I went up hills.

Now I notice that when I come to a stop a faint amount will come thru the mains.

I've read about vacuums but not sure where the vacuum lines are.

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  • Darren Weisensel Jun 26, 2009

    Thanks, but where is that?

  • Darren Weisensel Jun 26, 2009

    Where is the mode control switch?

  • Darren Weisensel Jun 26, 2009

    How do I do that? Thats a dumb question but is the only way to tear off the dash???

  • yadayada
    yadayada May 11, 2010

    no vacuum to mode control switch.



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I've had the same problem with my 1994 Grand Am. It was a vacuum leak (the controls for the vents operate by using vacuum). My battery leaks acid on the components below (still does--not sure why). There is a vacuum line that runs below the battery and when the acid builds up on the line, it eats a hole in it. I have fixed it a couple times (by inserting a thin plastic tube into the rubber hose at the break). Still can't figure out the battery acid problem, but I've got the vacuum line problem solved. I only have to repair it about every 3 or 4 years. Not sure if your problem is the same, but it could be. Just remove the air filter housing from the choke cover, and possibly you might need to remove your battery as well. You can see the vacuum lines easily then. They come from different directions and go into a bulbous shaped device in that area (not sure what that is--this last time I did the repair, I bypassed it entirely by connecting the line coming from the firewall area directly to the line going into the engine around the choke). Hope that helps!

Posted on Aug 05, 2009

  • Darren Weisensel Oct 03, 2012

    That was it. Vacuum leak under the battery!!


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You might have to clean out the ducts ..could be a heavy build up of dust of other can find very wierd things in cars tht arnt supposed to be there

Posted on Jun 26, 2009


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