I am getting no heat. I was having some intermittant problems with the temp switch not working, but now it doesnt work at all. This might help with troubleshooting the problem-
-Good vacuum pump (I just checked it)
-All of the selections on the heat/ac seem to work fine (it will blow on floor or defrost or vent when I select it)
-A/C also working fine
-Cooling system in good shape-no signs of mineral build up or corrosion and I recently changed the coolant and hoses

Is the temp control switch vacuum operated or is it electrical?

Where I park I am getting tons of pine needles falling into the cowling under the windshield- could they be jamming a door on the heater or something?

 

It has both. The vacuum operated actuator controls the recirculation door. It's the one down under the passenger side dash that you can see working when you switch to max A/C. From your description it sounds like it is functioning normally. There is also a temperature blend door actuator motor. That's the one that controls the temperature when you turn the ****, and (I think) is the likely problem.

You also need to check the hoses into and out of the heater core with the truck warmed up to make sure the core is not plugged.

 

Thanks for the reply. So any suggestions on how to check out the temperature blend door actuator motor and how to access it?

 

my door blend acctuator went bad too. very easy to replace, its the white box on top of your vents under your dash. i'll try to find a pic.

 

Like Glenn said. On top of the vent under the dash. It can be accessed easily by lowering the glove compartment door.

Once you find it (right in the middle of the door opening) disconnect the electrical connector, remove the bracket screw and lift the motor/bracket out as an assembly.

Checking it is easy. It's an electric motor. Turn the key on, set the a/c controls to heat, and turn the temperature **** hot to cold. If the actuator is working you will be able to feel/hear the motor turning the blend door congruent to the movement of the temp ****.

A note on installation. You may need to manually actuate the blend door to get the motor installed. It depends on what position it was in when it failed.

 

Thanks for the info!