Hello all - My '02 air conditioner (with electronic climate control) is acting strangely. Essentially, at idle or while driving around at speed, it works great. The temps are consistant with the charts I've seen on the site. However, when I drive the truck at very slow speed through my rut filled back field, the A/C shuts itself off completely - compressor not spinning.

The only way to get the A/C on again is to go to idle, or get to the road and speed up and then turn the A/C switch off and on. As long as I go slow (less than 5mph) the A/C will not go on no matter what I do.

Ever heard of this weirdness?? I have the exact same truck with an 8.1 and the A/C doesn't do this (???)

Kress

Any chance you have the AUTO button pushed? Sometimes it will shut down with this engaged.

Yes - I am certain the AUTO button is pushed - although I think I have tried to get it to turn on in manual mode as well.

I have been following the other active A/C thread and others are reporting their A/C shutting down at 90 or so degrees.

I wonder if I am just building up too much heat by essentially driving at idle speed across this field - especially now that it is getting hot here (90+).

Not exactly sure why it works at idle, other than that maybe there is sufficient cooling w/o the trans. in gear.

Thanks for your reply!Edited by: kress

kress, Probably about the same problem. There has been a problem with a low pressure switch. Mine will keep it cool at highway speeds but around town it will not. My wife's 2003 Tahoe will freeze us out around town and on the highway. Never have to have the Auto climate control set below 68. On my 2003 Duramax I have to run it as cool as it will go just to keep it bearable.

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<TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNABLE="off">03.5' duramax.. I have had the A/C shut down twice. Both times in high heat and after towing. I am taking it to the dealer to see what they say. Definately some problems here with the compressor or a bad sensor. I will let you know.</TD></TR>
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Mine--without climate crontrol--will "heat soak" and shut the compressor down. It happens on hot days (like summer here in San Antonio) when I have had the truck fully up to temp, shut it off for 15-30ish minutes, then crank it up again. When I do that, I need to get airflow through the condensor to cool it a bit before the compressor will kick on. Once it kick backs on it stays on even if I idle through town on a 95+ degree day. However, except for the "heat soak" phenomenon, my AC blows very cold.

afp1 - The "heat-soak" condition sounds like the exact same behavior that mine has. The A/C will blow cold under almost all conditions, except after sitting a little while and then driving at slow speeds.


I just took mine on a long trip down south pulling a small (8000lb) travel trailer and I ended up idling for hours in traffic (d#!n Pigeon Forge/Gatlinburg!!), and the A/C never once cut out on me.


FYI - I got about 12.3MPG driving south from Ohio with the trailer (avg. about 70 MPH). After dropping the trailer in Tennessee, I got 18.6MPG coming back to Ohio (going 75-80).

Just took mine in for similar symptoms. Easy fix for mine.... Leaky Schrader Valve (the Little thing that looks like a tire Valve Stem, thats under the thing that looks like a BIG Valve Stem Cap). Tech replaced, Vac Test System, recharge.... You can now hang meat in the cab at idle.http://www.dieselplace.com/forum/smileys/Big Smile.gifhttp://www.dieselplace.com/forum/smileys/Clap.gif What a Difference!

mine does the same while in idle around the lake on the farm and will sweat your rear off

Kress,


I forgot to mention that I took mine to the dealer and everything checked out fine. Go figure.............

I had a problem with my AC where it would operate for a period of time and randomly get warm (and humid). It didn't matter if it was on the highway or around town. I first had the system recharged and it improved but it didn't fix the problem.


A trip to the dealer cost me $43 in diagnostic fees and all I got was the TSB that provides a chart showing that my truck was operating in the "acceptable" range. The only problem was that it never failed for the dealer therefore it wasn't surprising that it was operating in the proper range.


I did a lot of research and determined that it was probably a faulty low pressure switch. The symptoms were identical to what a lot of others had described. There's even a service bulletin about this (which indicates to me that there is a significant number of low pressure switch failures out there). I replaced this relatively low-cost part and it fixed my problem.


The easiest way to tell if this is your problem is when the compressor stops, disconnect the low pressure switch connector and jumper the two pins on the harness side. If the compressor comes on, this is probably the problem (assuming your low pressure side pressure is in the proper range).

Thanks Captain. I am out of warranty so I didn't want to go to the dealer and incur the 'diagnostic fee' when I knew it would be difficult or impossible for them to recreate the problem.


Your suggestion on the low-pressure switch is a good one. I will disconnect it the next time the AC cuts out on me!


Since my AC works so well under most conditions, I think that the Schrader Valves and coolant level are OK.


Thanks to all for the replies!

BIGMOE,


There is a fix for your Dmax A/C. There is a re-program they can do for the compressor cycling intervals. And they also replaced some part for me, can't remember what it was. Since then, no problems. I live in Temecula, Ca. Temps in the summer 100+.


I brought mine in 3 times, and the third time was a charm!


If you did this already, I would keep bringing it back to the dealer till it is fixed. You should get cold air at idle too. Edited by: ronadycks

ronadycks,


I have an appointment to have mine fixed as soon as they get in the parts to fix it by TSB # 02-01-38-007C, from what I was told the parts are on backorder at the present. There has been some information about the TSB HERE (http://dieselplace.com/forum/forum_posts.asp?TID=12205&amp;KW=weak+ac)!


BIGMoe

Interesting. I chased down the TSB. Here is the step I think applies to me:
If the vehicle is equipped with a front license plate, inspect for proper installation. If the license plate bracket is installed upside down, it will block part of the two fresh air intake holes in the bumper. When the license plate bracket is installed correctly, the writing on the back of the bracket will be upside down.
The first summer I had the truck, the AC always blew cold. The second summer I had my new front end replacement bumper. I wonder if the aftermarket bumper is blocking those holes?
Blaine

On 90+ degree days my 2004 dmax will barely keep you from sweating. I even have tinted windows. Doesn't seem to matter if I'm idleing or going down the highway. Took it into the dealership and they said everything was fine just needed to take it out of autoamtic mode.


I also have a 2003 yukon with the same climate control set up and it will freeze you out set on 68 degrees. I put my dmax down to 60 and recirculate and doesn't get even close to being as cool.


I put thermometer in vent and won't get below 56 degrees while the yukon gets down to 42. Any suggestions of what I can tell me dealer to do since they seem to be pretty stupid.

I put thermometer in vent and won't get below 56 degrees while the yukon gets down to 42. Any suggestions of what I can tell me dealer to do since they seem to be pretty stupid.

ditto here. There is a new TSB out, 02-01-38-007c. See the TSB section for details.

Jim

Sounds like you are a candidate for TSB 02-01-38-007C that BIGMoe mentioned in the note above. This covers the redesigned accumulator that has just come out for the 2003 and 2004 Duramax trucks.

Read the following thread in the Second Generation topics area titled "New Truck-A/C Not Working Good". I think you will find that your problem is exactly the same as some of us have already experienced.

http://dieselplace.com/forum/forum_posts.asp?TID=10407&PN=3

I was told the parts are on National backorder, so you must get the dealer to write a repair order so they can order the part against a specific VIN. I am waiting for mine to show up.

Anyone who still is under warranty should insist on leaving thier vehicles at the dealer - and insist on a loaner, until it can be repaired. That is a comfort issue, and you should not have to sit in the summer heat, with an A/C you paid to have working.


I don't think I would stand for the parts are backordered thing, and be forced to drive in 100 degree heat with an A/C that is broken.


IF you make enough fuss, they will get your vehicle repaired more quickly, especially if they are putting up for the loaner vehicle.

Anyone who still is under warranty should insist on leaving thier vehicles at the dealer - and insist on a loaner, until it can be repaired. That is a comfort issue, and you should not have to sit in the summer heat, with an A/C you paid to have working.


I don't think I would stand for the parts are backordered thing, and be forced to drive in 100 degree heat with an A/C that is broken.


IF you make enough fuss, they will get your vehicle repaired more quickly, especially if they are putting up for the loaner vehicle.


Technicallly, GM wont foot the bill for a loaner unless the car is not safe or undriveable. No a/c does not really fall into either catagory.


Silveradogs, the cap should not cause or prevent a leak, its just there to keep the dirt out of the fitting, the fitting under the cap is likely your leak.

Ok try this- I was pulling the fifth wheel out in the Bad lands the past week, temps 90's A/C was Freeze your a!# off cold in the am but after several hours it would warm up in the truck to the point of sweating, Is this "heat soak"? Or do I have another problem to look for. http://www.dieselplace.com/forum/smileys/Cry.gifTrans temp was 205 +/- and water temp was 200 - 225 depending on the grade and how heavy my foot was. Juice was set to level 3 and EGT's ran 690 - 1050. The A/c did not improve even when the EGT's and water temp droped to the low end.

Anyone who still is under warranty should insist on leaving thier vehicles at the dealer - and insist on a loaner, until it can be repaired. That is a comfort issue, and you should not have to sit in the summer heat, with an A/C you paid to have working.


I don't think I would stand for the parts are backordered thing, and be forced to drive in 100 degree heat with an A/C that is broken.


IF you make enough fuss, they will get your vehicle repaired more quickly, especially if they are putting up for the loaner vehicle.


Technicallly, GM wont foot the bill for a loaner unless the car is not safe or undriveable. No a/c does not really fall into either catagory.


Silveradogs, the cap should not cause or prevent a leak, its just there to keep the dirt out of the fitting, the fitting under the cap is likely your leak.





I guess I pushed hard enough! They gave me a loaner for several days. But, there were other items that needed attention too. SO , you may be right. Still, as much as we pay for these vehicles, the inconvenience should be on GM.

I received a call from my dealer today, the parts for TSB # 02-01-38-007C came in today. http://www.dieselplace.com/forum/smileys/Big Smile.gif I take my truck in Thursday for them to install the parts. Started cooling off in Wyoming might be next summer before I can really give it a good test. I will post the results when they get it installed. Dealer didn't know about the TSB until I read it here and told them about it. Sure glad this website is here!!!!


A little over 11 months since GMCSID posted a message about GM going to fix the weak A/C problem.Edited by: BIGMoe

BigMoe - thanks for the update. I have just 'lived with it' so far this summer, but I would be very interested to know what parts are involved in the repair under this TSB. Given that mine is out of warranty, I will be doing the work myself.


Hopefully now that the weather is cooling off, there will be plenty of A/C parts available!!

I picked up my pickup this afternoon, they replaced the accumulator, the low pressure hose that now has a heat shield on it that goes above the turbo, a insulation blanket over the accumulator. and a new bracket to hold the accumulator. It was only in the 70's here today so not sure if it is going to help or not. If we get some warmer weather I will post if it helped. May have to wait until next summer.

Thanks a lot for the parts breakdown BIGmoe.

I was hoping it was something as simple as a switch, but I guess that was wishful thinking!