Heat not working

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Dec 26, 2014 | 09:09 PM

mckriesch

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Heat not working

Hello all,
I have a 1999 F150 4.6L. I have been having heat problems for many years now but I am now serious about fixing it. The AC works perfectly. The fan blows at all four speeds. It switches from floor to defrost to panel and everything just fine. The heater coil has been replaced. The heat/air conditioning switch(attached to the temperature control ****) has been replaced. The temperature control **** is not broken. Both tubes leading to and from the heater core are hot after the truck is ran for a few minutes so I do not believe that it is the heater core. When the temperature control **** is turned all the way hot, the air does get slightly luke warm but nothing to be considered heat. Does anyone have any ideas as to what the problem could be? Any help would be greatly appreciated.

Dec 26, 2014 | 09:14 PM

JWC 3

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Joined: Dec 2012

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From: Tennessee

Sounds like a blend door issue to me .

Dec 26, 2014 | 09:22 PM

mckriesch

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I had read about the blend door on another website and considered that but it also said that if it were the blend door that there would be a rattling or clanking sound when switching some controls and I am not experiencing any noise like that. is that true or could this still be the problem? also, if that is the problem, is it the door itself that I need to replace or a switch or what?

Dec 26, 2014 | 09:32 PM

JWC 3

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Joined: Dec 2012

Posts: 7,870

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From: Tennessee

I see them bad with no strange sounds . A Blend motor can be bad , or a broken door ( where the motor attaches ) . Get at it and see if the motor responds to switch input . Go from there .