heater a/c controll problem

94 c3500 dooley Heater controll is going bananas. The arrows at the left all flash and the air distribution does not work. Is it the controll or is a actuator not working and the display is saying that?

Have seen threads on this problems before, try searching for it.

I have a 90 K1500. Same issues. I ttok that panel off to access the contols. Bad news is that it is a circuit board that controls it. Unless you are super savvy at these things, you'll have to spring for a new control unit. Sticker shock about $300.00 LOL