My 2001 gmc sonama heater doesn't work ..only blows out cold air...what's wrong?

Blend Door Actuator Replacement 1999-2007 Chevrolet ...

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My problem in my 2004 chevy tahoe is that it will not blow out of the dash or ... onto the vent door gears ...

GMC Yukon AC and Heat Questions - Car Forums at Edmunds.com

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Jul 20, 2010 - 30 posts - ‎16 authors
I just don't get why that doesn't work right in the first place. ... I have 99 Yukon that has a problem with the front air. .... $55,000 for my GMC, I guess expecting cold air when we push A/C and getting 90 degree blast ... 2001 Yukon XL 1500 Front heat & air fine, rear ac blows hot as if heater is on in all settings. More results from forums.edmunds.com

sounds like water pump is broken

Hi Tamara,

Please review the following article to get an idea of what could be wrong with your heater.

Why Is My Heater Cold?

I had same problem on my 2001 gmc yukon. I found leak under my water pump. I replaced it myself and the problem was cured. heater wont work because there is not enough water to be heated for the heater.

Check your heater control valves.

make sure heater core is hooked up some times when the heater core goes some people just plumb it back ti itsself

There is a high probablity that your heater core may be plugged.

the most probabale cause of this would be a disfunctional hear core if you replace your heater your heater will more than likley work the the way it's supposed to

Disconnect the heater hoses from the water pump and the intake manifold. Get a compressor and blow out the hose (put the air hose into the the hose that came off the mainfold. then flush the system and replace the antifreeze.

the heater doesn,t work blows cold air