Ok guys, here is the deal. I have an 05 quadcab 1500 5.7 hemi. Over the winter my heater stuck on blowing only hot air. I have read all the post about the blend door issues. Yes I have gone through all the work to take the dash apart and check the doors thinking that was the problem. No luck, the doors are all OK. I checked the drive motor for the door with a 9v battery and the motor will turn both directions. So I figured it was the heater control unit in the dash so I replaced it. Once again not the problem. All in all the problem is the motor will not run and move the door. All other controls work just fine. Any ideas??? I am desperate!!! I have a $40,000 truck that has a shoe string tied to the door arm to keep the air working. Gotta a little redneck in me but dang this is rediculous!

 

Your air vents only blow hot air, even with A/C turned on? Did you replace the motor that runs the doors?

My quick fix version would be to bypass the heater core in the summer.