My heater is just blowing warm air. When a/c is on the air doesn't blow cold even though compressor is working and heater doesn't blow hot air when heat is on. Blower fan works fine. Vehicle temp runs normal so I don't think its thermostat. Everything seems normal. If it's the vent door stuck wouldn't it be stuck on either hot or cold? I haven't checked fuses yet. Truck did recently get worked on is there something that could have possibly been disconnected? I'm baffled need help!!!

 

Electronic or manual controls?

 

Manual controls and not dual zone

 

Sounds like the blend door is stuck in an intermediate position.

 

Check for a stripped temperature control ****.

 

Blend door is stuck in position, but it isn't because its stripped or broken. It doesn't seem to be getting any power to it. Is there certain wires I should test? Would a test light work? Is there a relay that could be bad? All fuses seem good.

 

I may be mistaken, but I thought it was vacuum operated? The actuator may be frozen.

 

The blend door is electrical, the rest are all vacuum operated.

There is a circuit board mounted so it engages with the door called the blend door actuator (BDA). It accepts the input from the temp control **** (potentiometer) and translates that dial position to a motor-driven movement of the blend door. You can dismount that actuator and test it visually to see if to is properly responding to the control. While it's off, you can also test the movement of the blend door manually.

Fuse F5 under the dash provides power to the BDA as well as the A/C compressor clutch as well as your backup lamps (easy visual check). If the backup lamps work, the fuse is good.

 

Well I got it tore down as far as I could for now. There's power all the way to the b/d motor and the shaft for door seems to be fine. So I am going to buy a new motor and hope that's the fix. Just having a heck of a time getting the floor ducting out to get motor out, but thanks everyone for your help!!