Lets see if I can explain this. I have a 99 F150 XLT. With the AC on and the fan in the lowest setting I get cool air turning the fan about 3 clicks AC goes full hot. I turn off system and it resets it self. Doing the same thing. To make matters worse it turn cool the other day so I wanted heat all I could get was cold air, after playing with it for a few minutes I got warm air on the panel setting. It seems to be electrical since I get both hot and cold air. Anyone have any clues and what to check?

Thanks,
Jimmy

 

1) Check for a stripped temperature **** first.

2) Check for a broken blend door or blend door actuator.

 

When it first started doing it, I was hoping it just a stripped temp ****. But that was good.

Have you ever changed a Blend valve or the door actuator? If you have is it a difficult job?