2000 Z71 A/C compressor shuts off - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chuckmc8 · 06-20-2009, 08:21 PM

2000 Z71 A/C is nice and cold and seems to work fine, but after its been on long enough to get comfy, the compressor shuts off (a/c light stays on) I have found that if I roll down the window for a few minutes the compressor comes back online and all is cool

Is there a reason that allowing outside warmer air in would cause the compressor to click back on? I have tried it w/o rollin down the window (just waiting 10 mins or so), but it doesnt come back on. Any ideas whats wrong? No unusual noises from the compressor and all the controlls seem to be working properly. thanks!

**bwood** · 06-20-2009, 11:38 PM

That usually is normal. When the air going over the evaporator (inside coil) gets so cold that the refrig doesn't pick up any heat out of the cab, the low pressure/cycle switch will begin to cycle the compressor. When you open the window the air going over the coil is warms up enough over the evap to transfer some heat to the refrig and will cause the low side pressure to come up and bring the compressor back on. If it has never done this before or is doing it more than normal, you might have the refrig pressures checked to make sure its not low. A low charge will make it cycle more.

chuckmc8 · 06-21-2009, 04:56 AM

Thnaks.I will have the pressures checked.

chuckmc8 · 06-25-2009, 05:58 AM

I changed the cycling switch and had the pressures verifed. It does seem to work ( compressor stays engaged longer) with the 'fresh' air elected rather than recirc. I also checked the relays and fuses.
There is lots of discussuion online with Google search about similar problems as this on these trucks, but I have yet to read a successful remedy. I'm sure that someone had figured this out...but not me! Any ideas to check next?
It cools fine and all controls seem to work properly. It just runs a while and when the compressor clicks out, it doesnt cycle back on? Thanks!!

Z-71 · 06-30-2009, 11:22 AM

When the compressor cycles off, does it still cool fine? If so, its totally normal, if it stays on all the time the evaporator will freeze up.

06-20-2009, 08:21 PM	#1
chuckmc8 It's alsways something..... Join Date: Nov 2008 Location: Douglasville GA Posts: 1,171	2000 Z71 A/C compressor shuts off 2000 Z71 A/C is nice and cold and seems to work fine, but after its been on long enough to get comfy, the compressor shuts off (a/c light stays on) I have found that if I roll down the window for a few minutes the compressor comes back online and all is cool Is there a reason that allowing outside warmer air in would cause the compressor to click back on? I have tried it w/o rollin down the window (just waiting 10 mins or so), but it doesnt come back on. Any ideas whats wrong? No unusual noises from the compressor and all the controlls seem to be working properly. thanks!

06-20-2009, 11:38 PM	#2
bwood Registered User Join Date: Jan 2003 Location: Denison, Texas Posts: 1,919	Re: 2000 Z71 A/C compressor shuts off That usually is normal. When the air going over the evaporator (inside coil) gets so cold that the refrig doesn't pick up any heat out of the cab, the low pressure/cycle switch will begin to cycle the compressor. When you open the window the air going over the coil is warms up enough over the evap to transfer some heat to the refrig and will cause the low side pressure to come up and bring the compressor back on. If it has never done this before or is doing it more than normal, you might have the refrig pressures checked to make sure its not low. A low charge will make it cycle more. __________________ 1998 GMC Sierra SLE 1/2 ton 2WD 305 Vortec -Gibson Stainless Cat Back Swept Side -SS Wheels 2005 Honda CRF250R 2006 Honda CRF150F

06-21-2009, 04:56 AM	#3
chuckmc8 It's alsways something..... Join Date: Nov 2008 Location: Douglasville GA Posts: 1,171	Re: 2000 Z71 A/C compressor shuts off Thnaks.I will have the pressures checked.

06-25-2009, 05:58 AM	#4
chuckmc8 It's alsways something..... Join Date: Nov 2008 Location: Douglasville GA Posts: 1,171	Re: 2000 Z71 A/C compressor shuts off I changed the cycling switch and had the pressures verifed. It does seem to work ( compressor stays engaged longer) with the 'fresh' air elected rather than recirc. I also checked the relays and fuses. There is lots of discussuion online with Google search about similar problems as this on these trucks, but I have yet to read a successful remedy. I'm sure that someone had figured this out...but not me! Any ideas to check next? It cools fine and all controls seem to work properly. It just runs a while and when the compressor clicks out, it doesnt cycle back on? Thanks!!

06-30-2009, 11:22 AM	#5
Z-71 Registered User Join Date: Feb 2003 Location: Vicksburg,MS Posts: 173	Re: 2000 Z71 A/C compressor shuts off When the compressor cycles off, does it still cool fine? If so, its totally normal, if it stays on all the time the evaporator will freeze up. __________________ 07 Chevy Vortec Max LTZ 4dr. Z-71 Stock for now 97 Chevy K-1500 Ext. Cab Step Side Tool box, bed rails HPP III, K/N, Flowmaster 285 Maxxis Mudders " If you can't drive the nail, get a bigger hammer" ( translation- Anything can be done with more power)



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