I have a 2001 2500 Ram w/Cummins 2WD. I'm at wits end. The AC works but if the blower is turned up some actuator actuates a gate in the system -thunk- and hot air blasts from the vents. The return air door below the glove compartment is not the issue, the mixer valve motor is not the issue...those I've checked without removing the engine and cutting into the area behind the dash with a torch. I can see no other way to access the climate control set up. None. I have removed 149234 screws and all the dash panels that don't seem spot welded into the frame...the thunk seems right behind the superstructure above the transmission hump. But I can't see anything moving. There is a vacuum actuator to the right of the gas pedal...but it doesn't seem to be actuating anything connected to the thunk of the gate that closes off the cold air. Is this something that can be done without torches and jaws of life?

 

Welcome to DF!

The flaps on your blend door are broken on the inside. There are two flaps that divert air over the heater core. If you remove the glove box you might be able to look over toward the center and see two control arms hooked together by a meta rod, thats where the flaps are. Look up heater treater for some replacement parts and instructions.

 

Thanks...I'll give the heater guy a call...this setup differs from the one in the video...the door connector arm is not externally visible with the entire dash laying back on the front seat. Hoping I don't have to remove heater core, condenser, entire a/c-heater box...not sure I'll live long enough to tackle that....