My 1991 Silverado digital climate control 'cold to hot' arrows begin to start flashing about 20-30 seconds after I start truck. At first it appears OK, I can run the arrows up from the cold to hot but then they start the flashing. All the other options/settings work but not getting heat now, just cool air blows. Truck has AC, all fuses are OK. Any ideas? Don't wanna buy a new climate control unit (If I can even find one) if it could be something minor. Any help appreciated. Jim

 

I as well had the same issue on my 91 silverado. For a while I would just unplug it and then re-plug it. The control box is bad. I had to buy a new one.

 

Thanks for letting me know. Going looking for a used one tomorrow in local j-yard. Jim