Question about 1999 Chevrolet Blazer

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AC is blowing out HOT air... How to get to the Blend Door to check it?

1999 GMC Jimmy starts blowing out hot air in the first 5 minutes running and then will not be cold at all. Seen information that the blend door or acuator is stuck or not working properly. How do I get to the blend door and/or actuator? no cold air is coming out and its charged

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  • inafog Jul 13, 2008

    1999 blazer,only getting heat from a/c- coolent is fine ,compressor working,bi-level controls work fine ,blend door is working behind glove box,the lines under hood are cold. Is there another doorway that could be closed and not letting the cool air through under the dash? I can feel the cool air when I got behind the glove box and ran my hand towards the firewall ( not blowing, but enough to know the a/c is working to that point)

    Where can I get a detailed diagram of my ductwork/dashboard. please help

  • Anonymous Mar 13, 2014

    heater blowing cold air

  • Anonymous Mar 14, 2014

    No heat but can hear the different in the air when I change from hot to cold

  • Anonymous Mar 17, 2014

    jetta blend door only blows hot air

  • Anonymous Mar 20, 2014

    The heat and cold air come out only through defrost.

  • Anonymous Mar 23, 2014

    cold air coming in dash drivers side replaced blend door actuator it don t sound like door is closing all the way

  • Anonymous Mar 27, 2014

    heater would not come on so I put in a new blend door actuator and now heat works and ac does not

  • Anonymous Mar 30, 2014

    how to check blend door for heaer


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No, you just need to fill freon gas.

Posted on Jun 25, 2008

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1999 gmc jimmy heater runs hot when turned all the way up but runs cold if turned down even a little ?

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Oct 18, 2016 | 1999 GMC Jimmy

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I have a 99 GMC Jimmy,4wd,4.3L,with climate control. I cannot switch mode on heat/ac,it constantly blow warm/hot air,also can hear a "clicking" sound behind dash,was told this a a "blend door motor"...

yes there is a procedure,but no short cut in removal of dash board.but my advised is that pleased contact a perfect electrician to remove it safely because of the electrical wires.

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Check to see if the compressor is coming on if not check the blend door actuator behind the glove compartment. If it is bad it is $59 at autozone

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Blend door 1999 jimmy

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Blows hot all the time.

I fixed the problem. It was the blend door actuator, but the wheels continued to turn because the reset operation requires resistance to know when the blend door is at its limit for the hot and cold side. At least that is what I assume. If the actuator is tested off of the blend door, it will simply turn until it can't turn anymore. After installation, it worked fine.

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