Hatzie

[Boog]

You are very knowledgeable about these hvac systems and their quirks. I have a couple of questions for you.
My 2003 Tahoe has 264,000 miles on it with dual climate controls, digital display.
I disconnect the battery between uses as we don't drive it often.
I have trouble getting heat right now. The radiator is good, heater core has been flushed, coolant level full, hoses hot to the heater core.
I found the only way to get good heat is to run the temp all the way up to 90* and to get good AC run the temp all the way down to 60*. At any other setting the temp wanders. It can turn from hot to cool in 2 minutes time on either heat or AC on it's own. As I adjust the temp the numbers are all over the place. I read where one guy pulled the temp knob and sprayed mass air flow cleaner in there to clean the potentiometer and it worked for his display. ?
I know the blend door actuator moves by input from the control panel so is my control panel bad? I see the usual recommendation is to do the reprogram. And why does an hvac system need to be reprogrammed so often? Thanks