Dual control ac blows hot air 2004 chev silverado

Douglass, Your A/C may have lost it's programming, blend door actuator could be faulty or A/C could be low on refrigerant. You may have to take in and have a good Tech. diagnose and estimate repair.
Check the attached links,instruction and guides, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."
Dual climate controls drivers side hot passengers side cold have 2004...
hot on driver side
Drivers side vents will blow hot air while is turned on but passenger side...

temp door is bad and needs replaced you can just see door motors under dash by gas pedal

If it has dual zone temp. control it is most likely the heater control panel.

you may need to have the controller re-calibrated. There is a TSB at the GM dealerships on this. What is happening is the the blend door control for the pass side has OVER-travelled and is stuck in a default position. You can try to pull the Blue fuse under your hood for the HVAC, for about 5-10 minutes and put it back in. (with the engine off) Then restart the truck and turn the Climate control back on, and push and hold the Auto button for 4-5 seconds

I have the same problem with my 2003 Silverado. I am not sure how to fix the problem but I'll keep looking and let you know what I find out. If anyone has any suggestions, it would be greatly appreciated.

You have a faulty switch. Go to the salvage yard and buy a used one, pull off the trim panel and replace it. I just did one of these last week with the same symptoms.

there is a motor actuator that moves these doors for hot and cold, two separate ones for either side. the motor unit for drivers side is no good and needs new one. replace this and all will be good.

You have dual zones that are controlled by temperature actuators the passenger side has lost its memory or has gone bad you can put it in self programming by disconnecting the battery for ten minutes then hook it back up start the truck turn the temperature control on but do not touch any other controls let it go thru the self programming for about 6 to 7 minutes then select your temperature you want if it still does not work properly you may have a bad actuator or a bad connection at the actuator

I had this happend to me on my 2004 2500 in july in S.C.I turned the key off and on 5-6 times and i have not had that problem again.

i have a 2005 and my # 4 setting on ac doesnt work