Hot/Cold air mixture switches to hot on its own.

Hello, everyone. My truck's cold/hot air mixture is switching on its own. I bought the flap door servo motor and plugged the wire in to test it. Before reinstalling I tried it a few times to watch the lever/arm turn back and forth. It worked fine but I noticed it switched back to hot on its own to the hot position while the knob was still turned to the coldest setting. Could it be the knob in the dash that's faulty? Thanks for any and all help.

 

I believe the potentiometer in the control knob tends to go bad and cause the blend door to randomly move to hot, all the FSM testing attached below.

 

Thank you very much for the help!

 

I've got the same thing going on in my '02... I do understand that these guides & schematic are for 03-04, but hopefully they're pretty similar and I can put them to use

 

Yep had to replace the climate control unit on mine I did the servo motor and the valve under the hood first.

 

So the HVAC panel came in and I swapped it out today. Seems to have cured the possessed temp control knob! Thanks for all y’all’s help!

 

Do you have the part number handy? I'll have to order one for mine. Thanks!