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1999 Jimmy AC cycles on & off


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caviterruptor
New User

Jul 22, 2010, 2:45 AM

Post #1 of 8 (6130 views)
  post locked   1999 Jimmy AC cycles on & off  

The AC compressor on my 1999 GMC Jimmy SLT 4.3L V6 with 98,000 miles cycles on & off with the clutch engaging/disengaging every 10 seconds. I recharged the refigerant. Any ideas?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jul 22, 2010, 3:16 AM

Post #2 of 8 (6123 views)
  post locked   Re: 1999 Jimmy AC cycles on & off  

Did you completely evacuate it and charge it with a weighed amount of refrigerant or did you just use one of those Wally world kits and just throw some more in?
Do you have a set of professional gauges to read high and low pressures?



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 22, 2010, 5:42 AM

Post #3 of 8 (6120 views)
  post locked   Re: 1999 Jimmy AC cycles on & off  

Begs the question - Why did this or why did you think it needed recharging at all? What were the pressures - BOTH - before you did anything?

T



caviterruptor
New User

Jul 22, 2010, 7:05 AM

Post #4 of 8 (6112 views)
  post locked   Re: 1999 Jimmy AC cycles on & off  

Wally told me it needed refrigerant, so I topped it off with a guage-less kit he recommended. I likened it to topping off the oil. Sounds like I should have consulted CarJunky first. Any chance of redemption?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 22, 2010, 7:41 AM

Post #5 of 8 (6108 views)
  post locked   Re: 1999 Jimmy AC cycles on & off  

Yes - we are here to help. It stinks that what is sold out there doesn't come with fair warnings - like a skull and X-bones! Seriously, the system may have NOT needed any refrigerant and could have been cooling poorly or not at all for 100 different reasons. The system is designed to shut down compressor when low pressure is too low, and or high pressure is too high.

That can happen for assorted reasons and now we (YOU) have an unknown charge in it. Ok - so what to do about that?

I can't re-write a two year physics course on A/C but there are some tell tale signs to look for now or plain send it out for a proper fill - EXACTLY by weight from a known, well holding vacuum. There is no dipstick for how much is in there - just good clues with pressure and temperature observations with assorted other items known working properly and you take measurements at a raised idle. 1,500 seems to be enough to get accurate readings and clutch must stay engaged or they can be forced but I'm not telling you how to do that right now.

Just warm up the vehicle for now. Turn on A/C and look at compressor and belt to see or hear if it's struggling. If so, unplug the compressor and tie the plug away in a safe spot as you could trash more than you could know or believe right now.

Low side is all the large gauge plumbing and high side is the smaller gauge plumbing. However low port is smaller than the large.

While compressor is running the low hoses (part metal) and accumulator on this vehicle should be cool or sweating not iced up. Smaller line from compressor should be warm to about too hot to touch. USE CAUTION PLEASE! It way too hot it's an indication that it's way overcharged or other problems.

Until you can get gauges which you can rent and learn how to use well first. Make sure fan clutch really pulls air well. Many are way too weak if not regularly changed and cooling performance will plummit and engine isn't thrilled either. Clean the condenser if dirty but note if it's oily! Bugs, dirt leaves or whatever it may be exposed to. If bad enough you may have to take top panel off and clean in between them - the condenser and the radiator.

That's what you can do now. Hunt down gauges if you want to do work on A/C yourself or farm it all out as the risks will bankrupt you doing things all wrong. Much of the equipment is rentable for just a full refundable deposit for safe return for free at some parts outlets. Ask locally if you don't want to buy everything which can get pricey to out of control when you are in the biz.

Locked up top in this section is CHARGING PROCEDURES - check that out. It's worth the read and will generate questions no doubt,

T



caviterruptor
New User

Jul 23, 2010, 2:05 AM

Post #6 of 8 (6097 views)
  post locked   Re: 1999 Jimmy AC cycles on & off  

Thanks for your time & response. Will let you know what I find.

C


Jimmy Ford II
New User

Aug 28, 2013, 5:55 PM

Post #7 of 8 (4108 views)
  post locked   Re: 1999 Jimmy AC cycles on & off  

I realize this is a dated thread, however, I suspect your SLT has the auto climate control system and if you happen to have the mode set to defrost, in this mode the A/C compressor cannot be turned off and recirculation setting cannot be selected.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 28, 2013, 6:04 PM

Post #8 of 8 (4105 views)
  post locked   Re: 1999 Jimmy AC cycles on & off  

You need to read the FORUM RULES before posting. You already know this thread is 3 years old.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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