Question about 2003 GMC Yukon Denali

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The rear heater does not generate heat - only cold air in vents

'03 GMC Denali - rear heater generates only cold air when fan is on. Is it an operator problem or is there a specific switch that needs to be set or is there a machanical problem? The air conditioning works fine and can be set to a specific temperature -- but not the heater. There is only cold air coming from the vents.

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  • magra1 Jan 14, 2009

    yes, the front air and heater works just fine. The problem only exists for the rear heater.

  • Anonymous Jan 17, 2009

    No rear heat, front works fine. I know 2 other people with the same problem.

  • wkwilcox Jan 18, 2009

    I also have a 2003 Yukon Denali. The rear heat and air doesn't work, but the front heat and air do. With the rear HVAC, the blower blows whatever the temp. is outside. Any suggestions?

  • acast Feb 09, 2009

    I have the same problem does not generate heat in the back it just blows cold air what do i do. the front works just fine.

  • butchhansen Feb 18, 2009

    The rear overhead heater control only allows cold air out the rear vents. No heat what so ever. Is there a vaccum line or a fuse that may be blowen.

  • Anonymous Mar 01, 2009

    We also have the same issue. Heat is fine in front. Blower works in back but only blows cold air

  • KYrazor1 Mar 01, 2009

    Same problem. No heat in rear.

  • Anonymous Mar 10, 2009

    same problem

  • Anonymous Apr 27, 2009

    Same problem here. 2006 Yukon Denali XL. Only cold air in rear vents.



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Does front air work properly? for heat i mean?.. the blend doors are suspect as well as the heater hoses to the rear core and its heater valve.. possibily the control head is to blame or?, but i cant tell from here

Posted on Jan 14, 2009

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I thought I had same problem . . . . until you turn the overhead switch completely to the right which I believe actually trips it to heat mode. hope this helps. Then back to the left copletely for air.

Posted on May 22, 2009


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