2 Vents A/c & 2 Vents Heat

[Rick Neighbors]

2004 Chevy 2500HD, Duramax/Allison, 4Dr pickup.

Driver side A/c vents blow cold, passenger side blows hot. Just started suddenly. Moving separate thermostat slide bars makes no difference.

Doubt if it is related, but just had 1 new battery put in drivers side, moved the driver side battery to the passenger side....disposed of the old passenger side battery as it tested bad.

On the way home from the shop, noticed the a/c heat problem.

Any ideas?

Can't take it to the dealer right now because I told them off on the warranty on my 7 year batterys. Seems the originals are just 3yr/36,000 miles, but if you buy the exact same batterys from them, suddenly they are 7 year batterys. Go figure

Rick

[Larry]

You need to get the actuators reprogrammed. If you disconnect both batteries for a couple minutes, then reconnect them both then start the truck without touching any heater/air conditioning buttons, the system will relearn in a couple minutes. If that doesn't fix it, you need to go to the dealer for reprogramming.
Larry

[Garth J]

Never just replace one of the batteries always replace both if one is bad the other isnt far behind

[Rick Neighbors]

Thanks for the replys.

Larry:

I left the A/c off for a couple of hours, and it " healed up ". :)

Garth:

Obviously you have not seen my checkbook balance.
:)

The shop where I had the batteries checked, is owned by a good friend. One battery was definitely bad. The other was just suspect. I put the new one on in the cranking battery location, I moved the suspect battery to the auxillary battery box. Everything is working fine now.

Rick

[Garth J]

Cant be any worse than mine but the battery issue is important
You wouldnt put only one new battery in a flash light
One old battery will draw on the new one ...Garth

[grancito]

Right, but worse than a flash light, these are in parallel and a small voltage difference will drag the good one down over night. However an old one with equal voltage will work OK.

[Garth J]

Grant it wont take long for the new battery to be draged down the same as the old one and you need two good batteries to get these engines to fire up properly