Heater control intermittent

[Dog Hauler]

My 01 2500 vent system goes from normal air (or a/c) to full hot randomly (I think). It usually returns to the cold position but not always right away. This is not cool when it's 100 degrees outside. When I do need heat, the heat control works but is either full on or full off. No in between setting can be obtained.

I've read quite a bit about the blend door motor system and most problems people are having are with the blend door failing in either extreme position. Not randomly switching back and forth.

Could this be a variable voltage problem? My first instinct was to blame a vacuum line but vacuum doesn't control the blend door.

Any help would be great!

Thanks,
Darren

 

[DavidC]

So maybe your coupling at the electric actuator is broke and allowing the door to move.

 

[Dog Hauler]

So maybe your coupling at the electric actuator is broke and allowing the door to move.

I'll definitely check that out.

 

[DavidC]

I'll definitely check that out.

Be aware it's not horrible but is a little of a PIA. You have to remove the Pass. side kick panel and sill plate to pull the rug back a little. Then you may (probably) cut a little foam from the floor to remove the back screw of the actuator. I'm not sure if mine was broke or I broke it removing the actuator. I had the new metal coupler on hand to install so it was no big deal. Somewhere on hear I did a writeup of the ordeal.

 

[DavidC]

You may read this, may help
https://www.turbodieselregister.com/threads/99-blend-door-and-coupler.268170/

 

[Dog Hauler]

You may read this, may help
https://www.turbodieselregister.com/threads/99-blend-door-and-coupler.268170/

Ahhh. Thank you.