I bought a 2000 Ram Cummins truck earlier this week. I got in this morning to go to Home Depot, and it was a little cool. I tried the heater and it did not work. The blower motor blows air, but it is not even warm.
When I got back I checked the hoses going to the heater core and both are hot, and took the glovebox out and felt the top of the heater core, it is hot also.
The clutch on the a/c continously cycles whether the a/c is on or off, I'm not sure if this is normal or would have anything to do with the heat problem.

The man I bought the truck from told me when I bought it the heater core had just been replaced due to a leak. The dealership performed the job. He says the heat worked before he took it to them, just had not had a need to use the heat because its been pretty warm here.

Is it possible the dealership let a wire unplugged somewhere or the control switch on the dash has when bad? Thanks for your help

Eric

 

Blend door motor would be my first guess. Turn the switch and listen for the motor or check power. Just replaced mine and it was very easy

 

Can you see the door if you take the glove box out? What position should the door be at in the different points on the control ****?

 

Uhmm I did not look, I knew it was the motor and just replaced it...

Hopefully someone else will come on and help.

 

Blend door "motor" is right next to the passenger side hump you can see it move when you move the temp sel sw. No need to remove the glove box, just go full hot to full cold to see if it moves the door.