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A/C HOT on one side COLD on the other


Full Member
Feb 20, 2007
After about a week of my truck sitting in the drive due to a dead battery, I replace the battery Wednesday night then Thursday when I decide to take the truck on some errands the AC acts up (Dual zone auto AC).

About 5 minutes after I leave my driveway I make it to the Interstate. After a few mins on the Interstate I feel the two drivers side vents blowing cold air but then I notice that the passenger side is blowing HEAT! Not warm air. . . HEAT. I started with the typical on/off, this button, that button. Finally turned the system off. Continued all evening last night as well even with 1hr parking breaks.

Same thing again this morning.   What could be the issue?
disconnect battery for 3 mins or so...

Need to reboot puter
ygmn said:
disconnect battery for 3 mins or so.     .     .    

Need to reboot puter

THANX!  I took two times.       After the first disconnect the passenger side started blowing cold while driver's side blew hot then after another disconnect all is normal again.       I appreciate the quick reply.   GEAUX TIGERS! (y)

Thanks again,
That happened to me last week. After I turned the truck off, problem didn't return. JohnB told me there's a TSB on that problem. Hopefully it won't return.

The very same thing happened to my 2004 Z71 Dual Zone Air 2 weeks ago.

The wife and I were out for a ride on some errands.  She looked over at me and told me that there was a better way to get her Hot than trying to fry her with the air from the vents.  I looked at her and told he she was not acting rational with that thought since it was the middle of the day and in plain view of all of the cars around us.  She replied to my statement by grabbing my hand and placing it ..............  Come on give me a break here!

She placed it on the Vent, where upon I received at least a 2nd degree scorching!  I am now called Fried Hand.

I tried to cycle it several times with off and on with the controller, shut the engine and restarted several times, and finally gave up and rode around with the windows down and sweat rolling.

The next morning everything was fine.  Go figure.

I mentioned this on another thread and received the same suggestion about the battery.  So no I know it it happens again, to disconnect the battery.  Only problem I will face is doing it one handed!  But then practice makes perfect does it not!!    :wave:
chevydan said:
The very same thing happened to my 2004 Z71 Dual Zone Air 2 weeks ago.

My '04 Dual Zone isn't freezing me out like it used to. It still gets cold both sides, I don't use it alot so I don't think it needs a recharge. I saw a post about something getting stuck, can't find it now and can't remember which component needs to be replaced or unstuck. (fan clutch ?)
Hot and Cold problem is caused by a damper position sensor getting mixed up.? The computer can't tell what position they are in, so one side diverts air through the heater core, and the other side send it through the A/C coils.? Usually turning off the vehicle completely and restarting it will fix it.? Next tactic is to disconect the battery for a while and then reconnect.? If all that fails, go in to the dealer for a damper position sensor inspection.