weird thing - over course of summer my '99 f150 seemed to be not cooling as well as usual. Then I noticed when I mover the thing all the way to the coolest postion it felt like it would "slip or move" back to less than that setting. But if I kinda moved it a couple times from warm to cold it would then hold.
I went out this morning and turned on the heat (38 and winters comin'), did the same dial thing but to heat side. Nothing really - seems if I kinda push on dial and turn it starts to open or close something - whichever is the case - but doesn't compltely do it. Air remains cold.

Is there a cable that runs off this to the heater? I assume it's not necessarily electronic since I could wiggle it to cold in summer. Thoughts or ideas?

This been a wonderful ride - looks almost showroom. Still - has 143K on it and starting to get quirky. And a dealer said I have a leaky head gasket on right side so I am getting a little worried - repair the bugs (est $1800 on gasket alone from dealer but I have never noticed anything wrong --- makes me wonder..) and now this heater deal. I know every vehicle has that point where one hits that decision time. I dread buying a new truck when I don't know if the need will be there in 5 years to have one.