Front Ac Blowing Warm Air

bulump · October 20, 2008

Hey guys....my 1st post on the forum (minus my intro)!!

My wife and I just bought a 2003 Suburban, and after getting a full tune up done on it, when I went to turn on the AC, the dash started blowing warm air, but when I turned on the rear AC unit, it was working just fine.

What do you think could be the issue here?

We did 'check' the AC prior to purchasing it, however, we bought during the evening and very well prbably felt the outside air coming in..... ugh.

Thanks!

Chris

Zembonez · October 20, 2008

Hey guys....my 1st post on the forum (minus my intro)!!

My wife and I just bought a 2003 Suburban, and after getting a full tune up done on it, when I went to turn on the AC, the dash started blowing warm air, but when I turned on the rear AC unit, it was working just fine.

What do you think could be the issue here?

We did 'check' the AC prior to purchasing it, however, we bought during the evening and very well prbably felt the outside air coming in..... ugh.

Thanks!

Chris

Sounds like a blend door issue. Not likely a big deal to fix. The system is obviosly circulating freon. The rear AC has an evaporator of its own. I bet there is an issue with a control motor or blend door that is stuck on hot up front.

alaska511 · October 20, 2008

Hey guys....my 1st post on the forum (minus my intro)!!

My wife and I just bought a 2003 Suburban, and after getting a full tune up done on it, when I went to turn on the AC, the dash started blowing warm air, but when I turned on the rear AC unit, it was working just fine.

What do you think could be the issue here?

We did 'check' the AC prior to purchasing it, however, we bought during the evening and very well prbably felt the outside air coming in..... ugh.

Thanks!

Chris

Sounds like a blend door issue. Not likely a big deal to fix. The system is obviosly circulating freon. The rear AC has an evaporator of its own. I bet there is an issue with a control motor or blend door that is stuck on hot up front.

To add to that Jim, the temp control valve that shuts off the hot water to the heater core may an issue as well. A quick test is to crimp off the heater hose

bulump · October 20, 2008

Hey thanks guys!!

Where is the blend motor? Is that something that is inside the bay or the dash?

I will try and crimp the heating hose as well, if that is the issue, what's its recourse?

Zembonez · October 20, 2008

Where is the blend motor?

Inside the heater core / evaporator housing under the dash (behind the glove box). There is a flap (or door) that controls where the incoming air is sent. It will be operated externally by an actuator. The blend door directs the incoming air through the heater core, through the evaporator, or a combination of the two, depending on the input from the AC/heater control panel. If that blend function is stuck on "heat" or even where it lets some of the air go through the heater core, it could result in no cool air from the AC. You should be able to see if the actuator is functioning by looking under the dash or possible removing the glove box door and running the control panel through its settings. We had to replace an actuator on my Dad's Chevy truck a few years back. His problem was opposite. It had no heat...

Maybe one of the techs will speak up and give us better info than I am able to give here.

Good luck!

Like Alaska said, if your truck has an external heater control valve underhood, I'd check that for sure too.

minibike132 · October 20, 2008

To add to that Jim, the temp control valve that shuts off the hot water to the heater core may an issue as well. A quick test is to crimp off the heater hose

We have not used that valve in quite some time. I can't remember the last model that was on but there is not one on this vehicle.

mr_bots · October 20, 2008

You might try something more simple first. I've read sometimes that it just gets confused and after a reset, it works fine. Unhooking the battery for ten minutes will reset all the various computers and modules, forcing the AC controller to relearn the door positions.

alaska511 · October 20, 2008

To add to that Jim, the temp control valve that shuts off the hot water to the heater core may an issue as well. A quick test is to crimp off the heater hose

We have not used that valve in quite some time. I can't remember the last model that was on but there is not one on this vehicle.

Oops, my bad. The last one I did was a 400 model. Sorry about that OP.

slayer305 · December 14, 2008

I want to bring this thread back from the dead.

I have a 2000 Silverado that is having the same or at least similar problem. It will blow hot air with the fan and temp control turned all the way off. It doesnt do it that often. Seems like when I turn to around 3/4 heat after being on full heat it does this. After that no matter what setting its hot air. If I turn the truck off and let it set for a while its fine again. Any and all ideas are appreciated.

slayer305 · February 22, 2009

I want to bring this thread back from the dead.
I have a 2000 Silverado that is having the same or at least similar problem. It will blow hot air with the fan and temp control turned all the way off. It doesnt do it that often. Seems like when I turn to around 3/4 heat after being on full heat it does this. After that no matter what setting its hot air. If I turn the truck off and let it set for a while its fine again. Any and all ideas are appreciated.

Bump