ford truck

[TonkaBass]

Well my truck is getting a little tired and she's starting to act up a bit. My temp is stuck on hot and no fuses are blown. Any ideas, I thought it's probably the climate control module, but don't know how to test it.

[Scott K]

Some detais here would be helpfull. Year, make, model, does it have EATC?

More then likely the blend door motor went bad, or something is stuck in there.

[TonkaBass]

Its a 99 f150 with ac, not sure what eatc is.

[Scott K]

It stands for electronic automatic temp control, dou you have push button, or knobs to adjust your heater?

[TonkaBass]

knobs that turn.

[Scott K]

If it is always blowing hot air, then it will be one of a few things. The switch that controls the temp, the actuator that moves the blend door (blend door motor), wires in between them, or a stuck blend door. Most comon would be the blend door motor bad.

[Scott K]

It looks as though fuse though fuse #5 feeds power to it. When you turn the blower on position 2, and turn the temp from cold to hot, back to cold, can you hear a change in the sound of the blower?

[Shack]

knobs that turn.

4WE pretty much covered all the regular items. I have also seen it when the black knob for the temp/blend control cracks on the backside and does not spin the metal stub sticking out from the temp control head. You can pull the knob off and check for a crack or spin the metal stub with a pliers.

Worse case would be a cracked plenum (heater box), causing the door not to move.