The switch on my a/c the cycles from floor/vent/de-frost etc. is frozen in place most of the time. Sometimes it works like normal. I rember when the truck was under warentty it did the same thing. I was told it was a check valve. Anyone know what and were this valve might be??? Semm to have gone bad again.

 

Do you mean that you cant turn the **** on the switch or that it turns but the airflow doesnt change?

 

The **** itself will not turn most of the time. Sometimes but few it turns like it should and the vent operate fine.

 

I think you're going to have to replace the switch.
It's easy to do.