AC Compressor Trouble\Electrical Issue

[debrockle]

Good Evening all. apologize for the novel but bear with me...I need a hand troubleshooting before the local dealer takes me to sizzlers.

 

2006 GMC Sierra 1500. Dual manual Climate controls. Crew Cab. 5.3 Liter.

 

I have an issue with the air conditioning ceasing to cool while driving after about 20 minutes (what seems). The only way I can get the truck to start cooling again (compressor to re-engage) is if I restart the vehicle ( or if I plug in the OBDII Code tester, more on that later).

 

I have taken the vehicle in for service twice. Once to check the refrigerant level which was fine. Second time they replaced the low pressure cycling switch off the dryer/accumulator (which seemed to be a common fix according the internets). All with no joy. I have a OBDII scanner and it shows no codes.

 

Today I made the connection that the compressor seems to stop when I bring the system off full dual cool to a warmer setting where the truck should be trying to maintain a cabin temp instead of full blast. Once all the fans slow down is when I seem to lose the compressor and the cooling even if I try full cold again. I repeated this failure while driving 3 times. However, while parked this issue doesn't seem to happen cycling the full cold to warmer.. cabin maintaining and back to cold. Very frustrating.

 

Final note: while checking the last time while driving and the compressor had stopped I brought it back to my garage... plugged in the scanner prior to restart to see if a code had popped. When I plugged that scanner in.. the truck did its normal thing being tested (kinda a flash on the dash).. however it also "reset" the compressor and it started again... and cooling like a champ without a restart.

 

So in a nutshell this is where I am.

 

Refrigerant is good.

low pressure cycling switch is new on the accumulator.

Lose the cooling/compressor when the cabin is not full blast and maintaining cabin temp.

Restart will bring compressor back to life or plugging in OBDII scanner.

 

So pretty sure the mechanical side is good. What is next to check or replace? HVAC control head? check another sensor?

 

Please help. Sorry about the novel.. but been at this for a while.

 

Hagendaus

 

 

[ARFFAZ]

Pull your HVAC/ECAS fuse in the engine compartment fuse block or disconnect battery for a few minutes. This will reset your HVAC system.

[debrockle]

Apologies. I did reset the HVAC as you suggested prior to all the troubleshooting. It did not correct the issue. Unit fired up at 74 degrees. Ran for two minutes. Shut off for 10 seconds.. fire engine back up. No joy...

[txab]

Check compressor clutch for proper air gap. If not running lightly tap face of clutch, see if it engages.

[Dnt]

I agree with the clown guy

[debrockle]

Per advice of Txab: Tap Tap engage...

 

So that action worked. Assume a failing or failed clutch then? I am going to start researching this now.. but in all of your experience is this something that a garage mechanic can fix without removing the compressor? Or new compressor/clutch unit... or is there a way to clean the clutch for better operation?

 

Thanks again for all the advice and any help in the future.

Edited July 13, 2017 by hagendaus77

[txab]

Air gap can be adjusted if it is out of spec. Could also be a weak failing clutch. Check air gap first

[Bigfutz]

After reading all the posts in a few threads, it looks like I have an AC compressor clutch issue on my 2003 Yukon XL. I went to go tap the clutch and felt my screwdriver drawn to the magnet. A little tap and it engaged. So now what can I do to make it through the SC summer? This one is pushing 400k miles, so I don't want to replace anything major.

[Bigfutz]

Air gap can be adjusted if it is out of spec. Could also be a weak failing clutch. Check air gap first

2003 Yukon XL... I found a couple of YT videos of various ways to shim the air gap... going to take a crack at that in the AM.

[Bigfutz]

2003 Yukon XL front of AC compressor - looks like a bolt is missing, which might explain why the clutch isn't kicking in every time. What size bolt goes here, and should I also have shims?

[Bigfutz]

2003 Yukon XL front of AC compressor - looks like a bolt is missing, which might explain why the clutch isn't kicking in every time. What size bolt goes here, and should I also have shims?

 

May be a minute on the photos. Apparently Photobucket is trying to extort money out of me.

Edited July 22, 2017 by Bigfutz

[muddkatt]

2003 Yukon XL front of AC compressor - looks like a bolt is missing, which might explain why the clutch isn't kicking in every time. What size bolt goes here, and should I also have shims?

 

May be a minute on the photos. Apparently Photobucket is trying to extort money out of me.

Even the link you posted does not work due to PB extorting money. Use Imgur to post photo.

 

This is what the link generates:

Warning: include(/mnt/den2-pri1-mnt/code/code/pb-htdocs/public/galleryd/desktop.php): failed to open stream: No such file or directory in /code/pb-htdocs/public/galleryd/index.php on line 122

 

Warning: include(): Failed opening '/mnt/den2-pri1-mnt/code/code/pb-htdocs/public/galleryd/desktop.php' for inclusion (include_path='.:..:../..:/usr/local/lib/php:/usr/share/php/Smarty') in /code/pb-htdocs/public/galleryd/index.php on line 122

[Bigfutz]

Enough about Photobucket, back to the AC. After coming up empty on a repair kit, I got a M6-1.0x20mm hex cap screw and reassembled the clutch including the single shim washer I found when I took it off. I pulled the A/C COMP relay and jumpered the contacts 30-87; clutch didn't pull in. So I took the clutch plate back off and removed the only shim. Repeating the test got a positive response this time. I cranked it to make sure the clutch wasn't rubbing when not engaged, then pulled the screw once more to add blue Loctite. Got my fingers crossed it will hold through the season.

 

My guess is this procedure was done already by the previous owner due to the lack of more than one shim, minus the Loctite hence the lack of the screw. It was difficult to tighten the screw as the shaft turns freely. I could have done a better job with an appropriate strap wrench, but I had to settle on using my relay jumper to engage the clutch and praying the Loctite holds.

Edited July 22, 2017 by Bigfutz

[bookgirl010106]

On 7/22/2017 at 4:26 PM, Bigfutz said:

Enough about Photobucket, back to the AC. After coming up empty on a repair kit, I got a M6-1.0x20mm hex cap screw and reassembled the clutch including the single shim washer I found when I took it off. I pulled the A/C COMP relay and jumpered the contacts 30-87; clutch didn't pull in. So I took the clutch plate back off and removed the only shim. Repeating the test got a positive response this time. I cranked it to make sure the clutch wasn't rubbing when not engaged, then pulled the screw once more to add blue Loctite. Got my fingers crossed it will hold through the season.

 

My guess is this procedure was done already by the previous owner due to the lack of more than one shim, minus the Loctite hence the lack of the screw. It was difficult to tighten the screw as the shaft turns freely. I could have done a better job with an appropriate strap wrench, but I had to settle on using my relay jumper to engage the clutch and praying the Loctite holds.

Out of curiosity, how did this work as a replacement bolt?  Did it last?  Just found out that my 2004 yukon denali is also missing the bolt out of the ac clutch and finding a replacement is impossible.

 

[sefiroxx]

When diagnosing, should use a full set of guages to evaluate hi and lo pressures when monitoring the clutch. That'll provide info as to whether hi lo pressure sensors are sitting the system down or not.

On the shim clutch discussion, new systems are often assembled with 1-2 shims to push the clutch as com the pulley. As the clutch wears down, shims need to be removed. If you are removing them, get ready to put in a new clutch, bearing and shims.