Mechanics

F150 HEATER NOT WORKING IN COLD WEATHER

1999 Ford F-150

Heater problem
1999 Ford F150 V8 Two Wheel Drive Automatic 145000 miles

in the summer heater works fine. In winter the heater blows cold air only. Replaced thermal switch on dash board. Checked heater core hoses under hood they are both hot when engine is at normal op. Temp.
signed, cold feet
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1999 ford xlt truck
December 9, 2009.




Check and test the thermostat and the heater control valve
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Tiny
Rasmataz
Dec 9, 2009.
Welcome to the forum, I'd have to check the blend door in picture. With the blend door in one position, ac, other position, the air has to go through the heater core.


http://www.2carpros.com/forum/automotive_pictures/170934_blend_doors_1.jpg


JDL
Dec 9, 2009.

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