Poor Air Conditioning Out Put

[DWB]

Bought my 03 CC D/A in Feb. and thought this was the perfect truck. Now that the temp. is 100+ here in the So. Ca desert, I find that my air conditioner is only putting out 70 deg. air (at the vent). Takes for ever to make the cab comfortable. Took it to the dealer and they played with it all day, then printed me out a TSB (02-01-38-007) that says many customers are complaining about A/C when temp exceeds 90 deg.
The TSB goes on to outline some things to check, then shows max. acceptable vent temp. table. Since it was 102 deg W/ 22% humidity the chart said 81 deg. at the vent was acceptable. When I said there is no way Chevrolet could expect us to drive a vehicle with A/C that works that poor I was told I should be gald mine was at 70 deg. and to have a nice day. Since my son's work truck (02 Chev 2500HD 6.0 Gas) has a vent temp of 40 deg in same conditions, this has to be a design flaw that came with the new body design. Anybody having similar problems or know of a fix?

[mackin]

Try insulating the engine compartment AC lines ..... You may pick up a couple degrees,or should I say drop ...

Mac http://forums.thedieselstop.com/ubbthreads/images/graemlins/shrug.gif

[GMCMax]

Make sure both passenger side vents are open. Closed vents create problems for dual climate controls. Hope this helps.

[tophog]

I have seen these same symptoms reported by other owners, and in most all cases replacing the A/C pressure switch has resolved the problem. I've heard the A/C pressure switch is "known" to be problematic. There is a separate TSB that covers the A/C pressure switch.

Warm Air (Replace A/C Low Pressure Cycling Switch) #03-01-39-007 - (05/29/2003)
Air Conditioning (A/C) Inoperative/Intermittent, A/C Blows Warm Air (Replace A/C Low Pressure Cycling Switch)
2003 Cadillac Escalade, Escalade EXT, Escalade ESV

2002-2003 Chevrolet TrailBlazer, TrailBlazer EXT

2003 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2002-2003 GMC Envoy, Envoy XL

2003 GMC Sierra, Yukon, Yukon XL

2002-2003 Oldsmobile Bravada

2003 HUMMER H2

[ThumbScott]

My 2001 duramax was not cold at all and my 2002 is not any better. I have noticed this to be a bigger problem when towing and air is on for long periods of time.

I am taking it in as soon as I get some extra time. The service where I live is slow on some of these issues.

[DWB]

Thanks for the suggestions guys, I will give them a try. Just doesn't seem right to have such poor A/C in an otherwise great truck. Also seems like if this is the way things are on the 03' there would be several other posts here trying to figure it out. Thanks again, being a new subscriber to the Diesel Page it's nice to be able to get some help from people who know!!!

[AlanL]

My truck ('03) is always so cold that I could hang sides of beef in it...

I haven't dealt with a really hot day and a long drive with it yet, but I haven't seen any of the problems that you guys are describing.

-Al

[Cancerman]

I have noticed the same problem when the temperature gets over 90F. I have found that if I run it on outside air to get the heated cab air for a few minutes, then switch to recirculate, the temp will come on down to 60F.
The AC is definately weak for us in the hotter climates.

[dsmith5740]

I've got the same issue with my '02 2500 HD Diesel (4 dr.) I live in warm & sunny Texas, and it takes FOREVER to cool this puppy down.

On the other hand, I've got an '03 Suburban, (1500 - gas) and also had an '00 Suburban - that bad boy will freeze your #@%*! off in just a few minutes.

Of note, both Suburbans and truck are set up with towing packages that allegedly have larger radiators and increased water flow.

Anyway, I get the same run-around when I complain about the truck's low a/c cooling capacity. One bone-head tried to go into the story that the a/c can only cool the air down by 30 degrees from o/s temp. I think he was confused with home systems. I'm not an a/c mechanic but I understand the theory. I'm pretty sure that the compressors on car a/c's are capable of having much greater temp variances than home systems. Besides, I just reminded him that my Suburbans can get meat locker cold in a short time. And oh, by the way, that compartment is MUCH larget in the 'burb than in my truck.

[GMC D-Max]

Just got my rig back from the stealer yesterday, one of the issues addressed was the poor AC performance. Their claim is (after running all the diagnostic tests) that the system is functioning normally, yet it blows warm air on a 90 deg. day. I told them that was all fine and dandy, and the truck would be back next time it got warm here. Thankfully, the climate around here is such that I only need AC a couple days out of the year, but I expect more out of a $40k+ truck.
One of the service writers did mention the low-side pressure switch, but of course they won't go the extra mile to replace it to see if maybe, just maybe it's faulty.

Since I also found out on this trip to the stealer that they "no longer offer loaner cars", rendering the guaranteed loaner clause in my extended warranty worthless, I guess it's time to look for a better service dept.

And, dsmith5740, any system that outputs a measly 30 deg. less than ambient temp. is within spec. Lame, huh?

[AlanL]

Since I also found out on this trip to the stealer that they "no longer offer loaner cars", rendering the guaranteed loaner clause in my extended warranty worthless, I guess it's time to look for a better service dept.


Doesn't this mean that they have to rent you a car or whatever? The dealership that I use doesn't have cars of their own to lend out, but when using the extended warranty, they rent me one from Enterprise and pay for it themselves.

-Al

[GMC D-Max]

Well, yes, they will provide a rental car, but that's only if they need to keep my vehicle overnight. Lot of good that does if I have running around to do that day. I'm supposed to pay 40k+ for a vehicle (and extended warranty) so I can have an entire day shot because I need warranty work? Granted, they do offer shuttle service (thankfully, I spent the entire day at my workplace, so I didn't need to go anywhere), but, they were very lax in contacting me about whether or not the truck was going to be done by the end of the day, whether or not I needed to be picked up from work, and so on. That's not a good way to do business. Again, maybe I'm expecting too much. Naw, I could deal with all this other BS if they'd just FIX MY FREAKIN' AC!!

[GMC D-Max]

After spending a little time trying to run down TSB's for my truck, and seeing some for poor AC performance on other vehicles, I got to wondering: how many of you fellas have noticed whether or not the engine cooling fan is running when you have the AC on? Does the AC get colder as the vehicle speed gets higher, like on the freeway? A TSB for the gassers calls for adding an electric cooling fan in front of the AC condenser to move more air over it. On the diesel, which is designed to run hotter, and as such has a clutch fan, is part of the problem that there's not enough air moving over the condenser core at idle or low speed??

[moisheh]

My 2001 diesel crew cab could be used as an extra freezer. Even in Phoenix with 112 degrees the auto air cycles down quickly.Engine fan seems to run a lot in this heat.

[tophog]

GMC D-Max, perhaps those 3 giant stereo amps I saw in your picts are dissapating so much heat the A/C can't complete? smile.gif No, really I wouldn't be a happy camper either. Before I bought my 03' I did a lot of research, etc. and was aware of all the A/C complaints before purchasing. I'm just waiting for mine not to work correctly ... call me paranoid. Have only used it once down here in Oregon and it seemed to work OK... time will tell I guess. Your truck looks sweeet.

[BobW]

Just came back from a trip to Arizona - 105o pulling the 5th wheel. AC kept things COLD!
Here are a few numbers from the Helm manual. About 40% relative humidity (Some small differences at different humidity levels.)

Ambient Air Temp Max Left Center Discharge Temp
66-75o 43o
76-85o 50o
86-95o 55o
96-105o 61o
106-115o 66o

Check out your system using these numbers.

[huntindog]

I'm in Phoenix as well, and dealers here would never make such a ridiculous claim.
My ac is cold in all conditions, as it better be.
We rarely have a day under 100 in the summer here.

[GMC D-Max]

Follow up to my stealer visit:
I checked the AC output myself last evening, using a Fluke model 78 with a thermocouple. Output from left center vent was OUT OF SPEC by several degrees (running 50-52 degrees), contrary to what the deal claimed. Then, this morning, I check it again, and it's running between 37 and 42 degrees. What gives? Sometimes it works, sometimes it doesn't (and that's always when I need it). I had to take the truck back in this morning for a TCM update (for OD lockout), and finally got them talked into changing the low-side pressure switch. I mean, what does it cost? Less than 20 bucks? Takes less than 2 minutes to change? At least it's a good starting point. (Of course, they didn't have one in stock, so I'm waiting for a call to bring it back down and have it installed. I also consulted with another GMC dealer in town, and they said they've changed quite a few low-side pressure switches.
I hope this takes care of it.
Wish me luck!

[GMC D-Max]

Originally posted by tophog:
GMC D-Max, perhaps those 3 giant stereo amps I saw in your picts are dissapating so much heat the A/C can't complete? smile.gif Yeah, but the pulsating subwoofer helps with the air circulation! ;)
:D

Actually, before I put the headliner back in, I insulated the roof with a foam liner material (made by Dynamat). I guarantee I'd never own a black truck in a hotter climate!

[afp]

I have been paying careful attention to mine for some time. It is into the mid 90s and humid here in the San Antonio area. (Humidity is "hard" on an AC system) 99% of the time the AC blows very cold. When I first start up the truck and it is cold, the AC blows cold. When the truck is fully warmed up, it blows cold.

However, when the truck has sit an hour or so and partially cooled off--but not completely cooled off--the AC blows warm when I am driving slow or idling. When I get my speed up, the AC blows cooler. After the truck fully warms up, it blows very cold again.

This must be the fan clutch. When the truck is cold, the clutch seems to be engaged--pulling an adequate amounr of air through the condensor--and the AC is cold. When the vehicle is fully warmed up, the fan clutch is engaged allowing enough air to be pulled through the condensor. When the vehilce is partially warm, the fan clutch is not fully engaged, so the coolness of the AC output is dependent on vehicle speer--the faster I go, the more air is pushed through the condensor.

I am guessing an electric cooling fan--set so it stays on unless the engine temp id very low--woud fix all this. Otherwise, I wonder if a new fan clutch might help--of course, it might do the same thing.

Blaine

[cowboywildbill]

Try replacing the A/C relay. It is located in the fuse box that is under the hood. It just plugs in like a circuit breaker. I had the same problem when my truck was new, a year ago. While on a trip to Fla. a Dealer in S.C. replaced the relay, took him about 3 minutes,it was under warranty and it has worked great ever since.Gets Ice cold, even in 100 degrees F. The part cost about $15 bucks.

[abrose]

I just purchased an 03 CC DA SB and I thought the AC was weak. It's in the dealer's shop at the moment so I'll have them check it out in light of all your comments. This dealer has been very good in the past so I hope to give a good report after this. This forum is great, I learned alot about my 85 6.2 and it is proving to be a great source for the DMAX as well. Thanks!

[oyazi]

Originally posted by Cancerman:
I have noticed the same problem when the temperature gets over 90F. I have found that if I run it on outside air to get the heated cab air for a few minutes, then switch to recirculate, the temp will come on down to 60F.
The AC is definately weak for us in the hotter climates. I find this comment interesting. I recall back when the Accura first came out, folks were complaining about the warm A/C. Turned out that it was set too cold and the humidity was freezing onto the condensor (or is it the evaporator now?) and clogging the essential airflow giving a false indication of a weak A/C. To change to ext air or to recirc w/heat should melt the ice. I'm wondering if thats what you were doing? I also recall like A/C problems during the SE Asian Games of '68.

[c130herc]

I have had similar problems with my ac also. When I am at idle it sometimes will not blow any cold air. The air is vent air and you can feel the humidity change. I have looked at my compressor and the clutch is engaged. It does this for about 10 to 20 min. I have took it to the dealer 5 times but it does not do it then and they wont do any thing. I am only 6000 miles from end of warranty and GM will not extend just the ac warranty.
If you get yours fixed reply back with what it was.
herc

[David Proske]

While I was shopping for my MAX, I test drove a model that had the auto ac. It didn't cool worth a damn. I then test drove a model with the manual controls. It cooled like a meat locker. I didn't like the yuppie auto ac anyway so I got the manual controls :D

[bobojay]

I've got a question. Yesterday we drove 150 highway miles in approx. 95 degree, 48% humidity heat. I noticed even with the fan turned on 3 & 4 I was getting very little flow out of my dash end vents (R&L). Checked both, they were open fully.
Also, the air temp coming out wasn't keeping up with the outside temp. We were both sweating somewhat, especially me since I was on the sun side.
Our truck has a noisy AC compressor as heard from inside the cab. You can hear it cycling on and off at all speeds. Sounds like a bad wheel bearing inside the cab. Standing outside the cab, it can just barely be heard.
When it's below 90 or after the sun goes away it'll freeze you out at all times.
One other thing. Yesterday when we left to come home, the truck had been sitting outside all morning heating up so I ran the fan on 4 and 5 to cool the interior. The outside air/recirculate button was on outside but it seemed the system was switching back & forth between recirc./outside by itself. This was weird, never had it happen before on any other vehicle. It was doing this while we were still in town cruising between 25 to 40 mph. After I switched back to 2 or 3 on the fan switch, it quit doing this the rest of the day.

Any ideas?

Oh yeah, I complained about the compressor noise last summer. The dealer said, "it's the Allison you're hearing", yeah right. ;)

[Minn-kota]

Originally posted by David Proske:
While I was shopping for my MAX, I test drove a model that had the auto ac. It didn't cool worth a damn. I then test drove a model with the manual controls. It cooled like a meat locker. I didn't like the yuppie auto ac anyway so I got the manual controls :D Guys without the "yuppie auto ac" are having problems too. FYI

:D

[jbplock]

My A/C has also been weak in hot weather. On another forum I read a suggestion to set the temp to 60deg. So for the last few days I’ve been running the auto A/C with both sides locked together and the temp set to 60deg. It is running much colder (with recircualte on or off). I also put a thermometer probe in the drivers side vent exhaust and I have been seeing temps down to 52deg with outside temps in the high 80's. At 78deg ambient, the vent air temps are near 40degF. This is also with the fan speed backed down a few notches. Tomorrow the forecast here is for mid 90's with high humidity so I'm anxious to see if the 60deg temp setting will make a difference. It seems that the 60deg setting prevents any warm air mixing and is equivalent to setting the temp dial to max on a manual system.

[Trippin]

I've got the same problem. Sometimes cold sometimes not. I haven't narrowed it down yet but it seems if I crank up the auto temp to 90 for a minute and then turn it off, then turn it back on and then down to 60 or 65 I can get cold air more often then not. Kinda like jiggling the handle just right. I'm going to the dealer next week.I'll keep you informed.

[Diesel Dragon]

Hi Everyone,

Been reading about peoples AC problems and have a few suggestions.

1. Make sure the temp setting is at 60 deg for auto AC control guys and all the way to cold for manual controls.

2. Turn the recirculating switch on, the AC can keep a much more comfortable humidity and temp level with the recirc on.

From what I remember from shop days the AC system in a vehicle is very large like a 2-3 ton rating, which is as big as a house central AC system rating, but the house constantly recirculates the same air, as should you do in your vehicle.

A vehicle is a very large heat source, with heat from the engine, tranny, exaust under the car, and heat from the sun on the exterior panels, which have very little insulation, and heat coming through the windows like a solar green house its tough to cool.

So if putting the lever on max cool and leaving recirc turned on dosent cool the vehicle enough I would take it up with the stealer and not let them off the hook till its fixed.

Also there are temp guidelines for how much the AC should cool an outside temp. I believe its a 40 deg drop or so. So I would imagine someone on this forum has acess to a factory service manual and can tell us the specs. Remember if its a particularaly hot and or humid day outside the AC will not work as good as a 75 deg low humidity day.

My wifes 03 Trailblazer just had the low side pressure switch replaced (a recall or TSB I believe) and the AC works fine again.

Well good luck to you and remember that if the AC is working well in the truck on the stealers lot next to you and yours is not you can tell him to fix it so it works like the other one.


Bye for now Diesel Dragon :cool:

[dave p]

this A.C. is weak. my 98 chevrolet 2500 had much better
cooling. my truck is white or i would really be in trouble. limo glass the back and side rear windows and it will help little. dave p