Jump to content

A/c Compressor Problems

dbbpeco

By dbbpeco
in Ask A GM Technician

Recommended Posts

dbbpeco New Member

dbbpeco

Posted
Posted

Ok, guys, here is a good one. 2000 GMC Sierra 1500, 139,000 miles, 5.3 engine. The a/c will run very cold, and as long as you want, as long as the truck is in park. Put the truck in drive and go 2-3 miles and the a/c compressor will disengage. Will run as long as you want as long as the truck stays put. Already tried changing the switch on the can on passenger side firewall. Didn't help, but was a cheap try. Why would the compressor be disengaging? Don't really want to change out the compressor, but may have to. WHAT IS THE PROBLEM? Friends say clutch may be overheating and need replacing. Is that the case?

txab Senior Enthusiast

txab

Posted
Posted

It could be low refrigerant charge or the air gap on the clutch has gotten too wide.

bill190 Enthusiast

bill190

Posted
Posted

The first thing to check is the refrigerant high/low pressure levels with a gauge set. If there is too much refrigerant or too little refrigerant it would activate either a high pressure switch or a low pressure switch.

 

The pressure needs to be "just right"! Note that these pressures change with the outside temperatures, so you need a chart which lists the pressures along with various outside temperatures.

 

If the pressure is as it should be, then I would look for other problems.

 

The pressures, your A/C system should have, would be listed in a GM factory service manual set for your year/model vehicle.

dbbpeco New Member

dbbpeco

Posted
  • Author
Posted
The first thing to check is the refrigerant high/low pressure levels with a gauge set. If there is too much refrigerant or too little refrigerant it would activate either a high pressure switch or a low pressure switch.

 

The pressure needs to be "just right"! Note that these pressures change with the outside temperatures, so you need a chart which lists the pressures along with various outside temperatures.

 

If the pressure is as it should be, then I would look for other problems.

 

The pressures, your A/C system should have, would be listed in a GM factory service manual set for your year/model vehicle.

 

 

I also should mention that we did take a piece of wire and try to hotwire the switch on the canister mounted to the firewall and the compressor would not kick back in. That's why we really did not think it was the pressure on the system. Also it will not kick back on until the truck has been turned off and has sat for a while. Just turning it off for a moment and turning it back on will not get it to run. I'll check the system pressure and rule that out though.

bill190 Enthusiast

bill190

Posted
Posted

There is probably also a "high" pressure switch. This cuts off the compressor if the pressure gets to be too high.

dbbpeco New Member

dbbpeco

Posted
  • Author
Posted
I am having a similar problem. Did you figure it out?

I have not taken it to a shop yet, but I will definately let you know when I get it figured out. please do the same if you get it first. Thanks!

  • 1 month later...
stvdalton Enthusiast

stvdalton

Posted
Posted
I am having a similar problem. Did you figure it out?

I have not taken it to a shop yet, but I will definately let you know when I get it figured out. please do the same if you get it first. Thanks!

 

 

 

I have a 1999 Chevy z-71 with a similar problem. It will work just fine, setting still or driving, as long as I leave it on regular a/c. If I turn it on max it will work fine until I start driving. Then it's kicks off and will not blow cold air until I turn a/c completely off for about 5 mins. NOt even if I turn it back to regular a/c. Once it stops blowing cold, it's done until you actually turn a/c off all the way. Pressures are fine on high and low side when it's on regular ac, but once it starts blowing warm air and it's on max, the hig side pressure is 240-260 sometimes a little more if you start revving engine. Mechanic don't know what to try. We blew out the radiator and all, thinking something was getting hot, just makes no sense.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • newdude
      2026/2027 Suburban — confirming AS3 bench delete with standard MagRide/Adaptive

      By newdude · Posted

      Here's the 2026 order guide - Vehicle Order Guide   RPO code "AS3"?  Not seeing it.  What is it supposed to be?  I see AS3 used a long time ago as some sort of seat option, but its not applicable to the current Suburban.    I see RPO code "AZ3" which is 1st row 40/20/40 split bench.  That is only on LS trim, which LS can't option any of the trick suspension.     2nd row bench power fold RPO code is "ATT".  So your dealer should be able to sort their locator to find matching builds by searching the combo of ATT and Z95 combined to find a 2nd row power fold with MagRide.     You can do the 2nd row power bench AND have MagRide, or Mag with Air on Z71, RST and High Country.     Here's a Z71 with 2nd row power bench and the Z71 Off Road Package which adds the Adaptive Air and MagRide - 2026 Suburban | Details | Vehicle Locator   Here's an RST with 2nd row power bench and the RST Capability Package, and RST Capability adds the Adaptive Air with Magride - 2026 Suburban | Details | Vehicle Locator   I can't find a High Country, but you can do it on there.  Requires the 6.2, and the Sun and Tow pack which allows you to then option the 2nd row power fold.  Black interior only.  High Country comes standard with MagRide and you can order the air if you get the High Country Deluxe, but Deluxe will take you to captain 2nd row.       You can do it at GMC on the AT4 and the regular Denali (not Ultimate) as well.  
    • newdude
      Looking at ordering a '26 WT because I want a std cab, std bed

      By newdude · Posted

      So.  Get this.  On the Chevy regular cab, you can get the factory remote start at the dealer from the accessories catalog.  BUT.  GMC, you can't.   Now...get this...GMC 2 door, you CAN get the power seat.     Go.  Figure.   Anywho.  are you trying to order?  Or locate?  Ordering for 2 door 1/2 tons has been stopped as of April or May?  So you won't be able to order.  You'll have to shop on the ground units or in transit units.     Ordering was stopped because the new trucks are coming.  
    • cherryred21duramax
      Tonneau cover that does not leak water

      By cherryred21duramax · Posted

      Thank you.  I really appreciate the well wishes.  I'm an engineer in the telecom industry, I know hardly anything about marketing.  Over the years I did some videos for nonprofits and web sites for small businesses and the seed was planted.  Agree with over-buying, I started shooting on an iPhone before I got my first DSLR and tripod.   I'm looking at trucks with potentially 150,000+ miles to keep the cost of entry low while focusing on the client experience and equipment.  Good wireless mics for interviews, the right lenses & lighting to look professional.  But I don't want to be late or break down, the stress of emptying a trailer & securing a rental truck right before a gig would negate any savings from buying a junker.  So anything that leaks water, has extensive rust, or generally unreliable I'd like to avoid.   Does GM/Chevy overbuild these trucks for upfitting?  I talked to a local upfitter, they sometimes tie lights & other 12V into existing circuits, which I always thought was bad.  Which is why I enjoyed the AUX upfit switches on previous trucks (odd they mostly come with off-road or work truck packages).
    • silveradosid
      injector cleaner 2021 2.7 1500 silverado

      By silveradosid · Posted

      i guess it might be depending on the type of driving. my 2.7 has 120k miles, changed the plugs at 70k and it runs as good as new. i have not used any injector cleaner
    • Atlas
      Looking at ordering a '26 WT because I want a std cab, std bed

      By Atlas · Posted

      GM's are stainless and have a fairly robust powder coating, although, still not worth $850 in my opinion. They will hold up a lot better than their cheaper steel aftermarket counterparts.   What I like about the GM step bars is dealers will often equip their dealer stock with them. Lots of margin. Which means a lot of people end up buying them because they're already on the truck, even if they don't like them. So it's pretty easy to find brand new takeoffs with hardware on Marketplace and Craigslist for about $250.   That's what I did for my crew cab. I wanted ZR2 rock rails for the look, but with the ability to bolt up GM's assist step package. From GM it's about a $2500 accessory all in. The old folks in my life can't get in the truck without steps. I found the whole package on marketplace for $180.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...