A/C Occasionally Blows HOT Air!!

Status
Not open for further replies.
V

Vortec_4300

Joined
May 18, 2005
Messages
111
Location
Levittown, PA
Hi All -

I have a new Chevy Silverado pickup truck with the 4.3 liter V-6. It is almost 4 months old.

Last week, on a long road trip, my A/C stopped blowing cold air and began blowing HOT air (as in, air from the heater, not outside air.)

I played around with the switches to no avail.

Several hours later, after the truck had been parked for several hours, the A/C worked just fine.

The same thing happened yesterday afternoon - the A/C went from blowing cold air to HOT air (even when I put the switches to the outside vents, it continued to blow HOT heater air.) After the truck was parked for several hours, the A/C worked just fine.

The truck is under warranty, but I am sure that this is one of those issues which won't be evident when I actually get the truck to the dealership for a service call. I guess that I am looking for some information so that I can go to the dealership ready to discuss this problem with the service manager a little more intelligently.

Thanks for all responses!
 
it could be a number of things, from just low on freon to an electrical problem with the AC clutch. The low on freon part will be easy for them to check and they should do it first without question.

If it is low on freon, make sure they figure out where the leak is and fix that as well.

After that, it's pretty much going to be that they will have to wait for it to fail before they can fix it.
 
Does the air start coming from the floor outlets or does it just start blowing warm air? I know Trailblazers and other GM vehicles that use a cycling clutch system, the low pressure cycling switch can stick and cause a symptom like you desctribe. Don't know if your truck has that cycling switch. Probably does. The cycling switch is screwed to the side of the receiver-dyer onto a Schrader valve. When it stops cooling, a light tap on that switch with a screwdriver handle to unstick it will verify if that's the problem.
 
Leaking vacum allowing the doors to switch, next time turn it off for a minute (The entire climate control system) then turn it back on
 
Most GMs these days including the trucks have electric motor "actuators" that operate the ducts with position feedback to the computer. Not vacuum like in the olden days...
 
quote:
Originally posted by tblazed:
Most GMs these days including the trucks have electric motor "actuators" that operate the ducts with position feedback to the computer. Not vacuum like in the olden days...
Click to expand...
Bingo.

Check with the dealer. There is a chance of a TSB or special service message that covers your problem. Wiring, a bad temperature selector switch or faulty blend door actuator/motor can cause intermittents like this.
 
Sounds like you are under warranty, but...
The symptoms you describe are classsic 'icing up' problems in the lines because of moisture. You may have a pressure problem, or a bad switch, however.
 
Thanks all.

I'm going to make an appointment with the dealership, take a printed copy of this thread when I meet the service manager, and make him walk dow the list with me and investigate everything on here.

He may or may not do everything, but I will sure as heck get it documented on a work order.

This website is one of the best things going.

Thanks again!!
 
UPDATE -

The problem was diagnosed as a faulty low pressure switch, which has been replaced under warranty.

Thanks to all once again for the help!
 
We have a winner! Mr T. Blazed! Honorable mention to mechtech. Please collect a complimentary Fram oil filter on your way out.
 
UPDATE AGAIN -

The problem returned yesterday afternoon, on a 50 miles drive to the Jersey Shore.

Cold air blowing, then hot air.

I noticed that the hot air appears to be blowing only from the driver's side vents, not the passenger's side. I don't know if this occurred before having the low pressure switch changed.

What a drag.

I'll be scheduling a return to the dealership for another look-see.
 
UPDATE on 06/17/06:

This problem had recurred, off-and-on, for the past several months. I had taken the truck back to the Chevy dealer on two prior occasions, but because the problem was not evident during those visits, there was nothing that the dealer could do.

On Wednesday afternoon, I was headed home from work early when the problem recurred. I drove directly to the dealership and dragged a service rep. over to the truck to see the problem firsthand. She brought overt he shop supervisor who checked a few things, and then announced that the problem was a bad actuator on the driver's side of the cab (I hadn't noticed previously, but when the problem would occur and hot air would blow out of the vents on the driver's side, the passenger's side vents were still blowing cold air.)

My truck was fixed, I picked it up the next day, and I am now content that the problem has been addressed.

One item of note - the actuator apparently didn't need to be replaced - apparently the HVAC computer needed a software upgrade. There was actually a TSB issued about this problem, so after a flash upgrade, the problem should be addressed, according to Chevy.

I find it odd that there was a TSB that dealt with this problem, but the mechanics at the Chevy dealership (Reedman Toll in Langhorne, PA) did not figure this out on the three previous occasions that the truck was in for this specific issue.

In any event, I thought that this information might help someone who experiences a similar problem, so I thought I would post an update.
 
Well, well, well....

The problem recurred again last week - with only 40 miles to go before my warranty expired!!

This will have been the 4th time that the vehicle was in for the same issue.

I read the service manager the riot act.

(Actually, I told him that I blamed myself more than I blamed him - I bought a Chevy, which was my first mistake, and I bought it from his dealership, where they apparently could not repair a simple problem in the dashboard, which was my second mistake.)

The actual motor or "actuator" (it is called a temperature control motor on the receipt that I got from the dealer) was replaced on the driver's side, so let's hope this is the end of this ordeal.

PS - I don't consider buying a Chevy to be a mistake - this could have happened to any other brand of vehicle, I'm sure!
 
quote:
Originally posted by Vortec_4300:
UPDATE on 06/17/06:

This problem had recurred, off-and-on, for the past several months. I had taken the truck back to the Chevy dealer on two prior occasions, but because the problem was not evident during those visits, there was nothing that the dealer could do.

On Wednesday afternoon, I was headed home from work early when the problem recurred. I drove directly to the dealership and dragged a service rep. over to the truck to see the problem firsthand. She brought overt he shop supervisor who checked a few things, and then announced that the problem was a bad actuator on the driver's side of the cab (I hadn't noticed previously, but when the problem would occur and hot air would blow out of the vents on the driver's side, the passenger's side vents were still blowing cold air.)

My truck was fixed, I picked it up the next day, and I am now content that the problem has been addressed.

One item of note - the actuator apparently didn't need to be replaced - apparently the HVAC computer needed a software upgrade. There was actually a TSB issued about this problem, so after a flash upgrade, the problem should be addressed, according to Chevy.

I find it odd that there was a TSB that dealt with this problem, but the mechanics at the Chevy dealership (Reedman Toll in Langhorne, PA) did not figure this out on the three previous occasions that the truck was in for this specific issue.

In any event, I thought that this information might help someone who experiences a similar problem, so I thought I would post an update.
Click to expand...
Just trying to see this from the dealers viewpoint, but when you took it in the first time and said,"my ac started blowing warm", why would they initially just look at the driver side actuator only if what you were describing sounded like the whole a/c system quit cooling?
dunno.gif
 
Status
Not open for further replies.

Similar threads

B
Max A/C = closed heater core valve
Replies
14
Views
999
meep
F
Need Some HVAC Advice 2003 Suburban
2
Replies
23
Views
782
Fitz98
BAJA_05
Added R-134A to AC. Now just blowing hot air???
2 3
Replies
45
Views
3K
wtd
Passport1
Need A/C Recharge Advice
Replies
15
Views
893
MSCH
D
Where is Vent Temperature Air Out (TAO) Sensor (Honda/Acura Climate Control) - if it exists?
Replies
4
Views
752
SHOZ
Back
Top