Topic: AC Problems, Need some ideas here please.

[Fred]

Wasn't sure where to put this so I stuck it in here. A couple of weeks ago my battery bit the dust. Got it replaced (see my DIY), started up, life is good right. Next trip to work I have the a/c on and I go to adjust the temp up just a little bit. When I turn the temp knob CCW one click all of a sudden it's like turning the heat on. Hot air. I found a thread in Joe's Garage about getting the temp doors in sync so I tried that. Now when you adjust temp it stays cool for about five seconds or so before blowing hot air. Temperature switch? Something else? I did a search here and on the big board and didn't find anything of use. I know y'all can solve my problem.  

[Sol Asylum]

I don't often pre-apologize for my comments but sorry for the following.

Have you tried moving out of Texas? 

[Fred]

Haven't tried but have thought about it many times.   

[DeepBlueGXP]

Did you see this thread about AC
http://kappaperformance.com/forum/index.php?topic=2664.0

[Fred]

Yes sir, I did. I did the mode door reset and it gained me few more seconds before the hot air started blowing. Maybe once wasn't enough. Maybe I should stop talking to myself. 

[U4EA]

Have you determined if the compressor is running or not during the hot air cycle? I would think it is not. Just curious.

[Fred]

I have not. Will check it out. Thanks.

Update----the compressor remains running.

For clarity......

Temperature selector all the way to the left in coldest position
A/C on and blowing cold air
Temperature selector turned one click off coldest position
Air starts blowing hot like the temperature selector was turned all the way to the right.
Air remains hot in any position other than all the way to the left.

[DeepBlueGXP]

Sounds like the mode door reset didn't take.  Try again and if no joy, take it in to the dealer.  I know that sux since you have an 06 and warranty may be up.

[Fred]

No maybe about it. It's been up for awhile.

[Critterman]

Just for ha-ha's, set it in re-cycle mode and then move the dial

[U4EA]

Sounds like the mode door reset didn't take.  Try again.

What he said!

Just for ha-ha's, set it in re-cycle mode and then move the dial

What he said!
If it still only cools on coldest setting my guess is the DASH CONTROL UNIT #15865389 $291.99 GMPARTSDIRECT. This is purely speculation. Where is that wiring diagram when you need it? At least it cools, makes parts of a man disappear with no adjustment though. I can hang meat in my GXP here in Texas in August.

[Fred]

Well I tried just for ha-ha's and it does the same thing. It was working fine up to the battery going poof! Thanks for the part # U4EA. I think you may be right on with your diagnosis.

[Critterman]

I would try the reset one or more times,  it sounds like the heat control door only has two positions at the moment, it is either fully open or closed.  If that doesn't work then you have two options:

1. dealer
2.  buy the part and replace it yourself.

Do you know anyone locally who can test it for you, perhaps a good local garage your trust?

[lil goat]

I do not know why this is happening but I can pretty much guarantee that for some reason your heater core(little radiator inside car) is not being shut off. It fills with water from the radiator when the heat is on, should not fill when AC is on, it is heating your cooled air by blowing across the heater core that should have no water in it but for some reason does. I have no clue where the valve the shuts of flow to the heater core is unfortunately.

It is not unlikely that the heater core shut off valve is vacuum operated and the vacuum hose got disconnected when you replaced the battery.

I am not a mechanic but I do play one on TV

[Critterman]

Jim,  I think you are being old school now.  I don't think the water flow is controlled any more by a valve instead it is a door seperationg cold from hot.  I could be wrong and it won't be the first time.  However since it is either on or off, I don't think it is a vacumn operated control.  It sounds more like a reostat that has shorted like a multi position fan switch that only works on full or off.

[lil goat]

There is still a heater core, there is also still an evaportor, they are co located at the back of the dash against the firewall. The heater is still nothing more than a radiator full of hot water with air blowing across it, the evaportaor is behind it and the same blower blows air across it to cool the air. It is old school yes, but not much has changed really. If your car is running hot you still can turn on the heater and open the heater core to help cool it down. When the AC is on the heater core should be closed off. If it is full of hot water exactly what he described would happen, it is pretty simple really. The part is called an:
Actuator , Mode valve
AIR CONDITIONER & HEATER » Upper case
Pontiac › Solstice › 2006-2009
List Price : $ 37.17
Your Price :$ 29.74

I am sure is is a biatch to get to but sounds like it is not working. I am just trying to figure out why when he changed the battery it quit working. Sounds like something got unplugged or a fuse blew if it is an electric controlled valve.

[Sol Asylum]

I think that Goat might be on the right path here.  The shop manual calls out how to replace the mode actuators, it looks like there are two for air temp.  These actuators move air valves which route the air flow over the heater core or evaporator.  There does not appear to be a valve that controls coolant flow to/from the heater core.  These actuators have to work together and in order to do so they have sensors that tell the system what position the actuators are in.  The manual says that when you replace them you have to "start the engine and let it run for one minute to calibrate the actuators."  There is then a tip that says "Do not adjust any controls on the HVAC control assembly while the HVAC control assembly and actuators are calibrating. If interrupted improper HVAC performance will result."

My guess is that for some reason when you replaced the battery and then restated the car the encoders on these actuators got miss calibrated.  For the hell of it try disconnecting the negative terminal on the battery and letting the car sit for 10 minutes or so and then reconnect the battery.  Then start the engine and let it run for a few minutes without touching the HVAC controls.

Its worth a try and can't hurt anything unless you try to disconnect the pos terminal first and short a wrench to ground, thats why I said disconnect the neg terminal.

[WedPro]

Wasn't sure where to put this so I stuck it in here. A couple of weeks ago my battery bit the dust. Got it replaced (see my DIY), started up, life is good right. Next trip to work I have the a/c on and I go to adjust the temp up just a little bit. When I turn the temp knob CCW one click all of a sudden it's like turning the heat on. Hot air. I found a thread in Joe's Garage about getting the temp doors in sync so I tried that. Now when you adjust temp it stays cool for about five seconds or so before blowing hot air. Temperature switch? Something else? I did a search here and on the big board and didn't find anything of use. I know y'all can solve my problem.   

Had the exact same problem. My Dealer replaced both mode door actuators and the control head. It lasted a very short time and the problem returned. Took a while for GM to come up with a fix. Now there is a fix (Document ID: 2199072   #PIC4995 dated 10/10/2008). This involves adding a resistor to the control head to prevent feedback voltage. It has worked correctly for 2 months since the repair.

[U4EA]

Intresting.
I believe the GM part # on the original control unit has been discontinued. Tried to enter the original part # into parts search, comes up nothing. The current control unit listed is a different #.
New # 15865389
Old # 15286623 maybe?

[Fred]

Thanks for chiming in WedPro. I'll be sure to take this info to the dealer when I take it in. Curious though......did yours just start or did you have a battery issue also? 

[WedPro]

I live in Florida. When using the AC, it was always left at the coldest setting due to the outside temperature here in summer or AC turned off with the top down at other times. First noticed the problem when returning from the Tail of the Dragon in 2007. During the 13 hour drive home the temperature got very cold inside the car and it was raining outside. I tried to regulate the temp and it went to full heat. After that it stayed on full heat no matter where the dial was set. I discovered the only way to get cold air back was to pull over and turn the car off. Upon restart the AC would blow cold air again. My dealer could find nothing wrong or duplicate the problem because you have to drive the car at highway speed for a while before it acts up. I have complained to the dealer once a year since and the last time he found a bulletin with the exact problem described word for word. So far, the addition of the resistor to the control head has fixed it.

[Fred]

Similar circumstances here. I live in SE Texas so A/C stays pretty much all the way cold except when the top is down. With mine though cold temperature will return when the dial is placed back to the coldest position. Just no way to regulate it. Glad it's getting back to top down weather here. Thanks again for the input.