Air conditioner not working

Tiny
ROBERT S
  • MEMBER
  • 1998 CHEVROLET SILVERADO
Air Conditioning problem
V8 two wheel drive automatic 195,000 miles.

When I hook up the gauges low was 95 and high was 75. I jumped the compressor to the battery, engaged the compressor, and the low went to 30 and high went to 150. So, I started checking the electrical. The relay does not engage. So, I jumped 87 to 30 connector and the compressor engaged. So, I checked 86 and 85 connectors no power on either. I jumped the pressure switch on the accumulator and nothing. So, I tried to jump the other switch on high side of the compressor still no luck. I cannot find a electrical diagram (even in the Haynes book). Oh, I checked all fuses as well.

Help, what powers the relay to close?

Does the pressure seem right. The low is double when the compressor is not on and then balances out correctly when the compressor is running?
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Wednesday, May 21st, 2008 AT 9:49 PM

12 Replies

Tiny
MASTERTECHTIM
  • MEMBER
Here are the complete wiring diagrams for the air conditioner and a couple of guides to help you do some testing.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

and

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak


http://www.2carpros.com/forum/automotive_pictures/139033_ac_1.jpg



Check out the diagrams (below)

Cheers,
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Thursday, May 22nd, 2008 AT 6:22 AM
Tiny
ROBERT S
  • MEMBER
Thank you for the diagram. I will check them. Does the system pressures usually works this way?
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Thursday, May 22nd, 2008 AT 8:21 AM
Tiny
MASTERTECHTIM
  • MEMBER
They seem a little low to me, was it super cold outside? I would try putting a little in to see what happens.

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

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Friday, May 23rd, 2008 AT 6:03 AM
Tiny
ROBERT S
  • MEMBER
Thanks, for the wiring diagram. Found the issue the clutch cycling switch was out I changed it and BAM! All fixed.

Thanks, for everything this site rocks water back
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Friday, May 23rd, 2008 AT 9:51 AM
Tiny
MIKEM1837
  • MEMBER
I had the same problem. Just and added a little Freon and the system works perfect thanks you guys!
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Thursday, June 26th, 2008 AT 12:03 PM
Tiny
KAYLEENME
  • MEMBER
  • 1998 CHEVROLET SILVERADO
Air Conditioning problem
1998 Chevy Silverado V8 Four Wheel Drive Automatic

My a/c isn't working the fan blows but the compressor dosnt't seem to be coming on. In fact, I can see that the pulley isn't turning. I checked fuses. Any other ideas?
Thanks
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Friday, October 13th, 2017 AT 10:02 AM (Merged)
Tiny
JOEBOXER
  • MEMBER
Kayleenme, I got about the same problem as you, mind will run for a while throwing out cold air, how long, I don't know then suddenly it just throws out warm air. In the fuse box under the hood, you will have 4 relays, one is for AC. I switched the AC and the brake relay to see if it will stay on. I have to wait to see if it working right.
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Friday, October 13th, 2017 AT 10:02 AM (Merged)
Tiny
FREAKY
  • MEMBER
I have a 1995, same thing, ice cold for years, two days ago, hot, hot, hot. I read somewhere that lack of freon will prevent the clutch from kicking in properily. So I added a can I bought at Autozone. And now it's fine. ICE COLD!
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Friday, October 13th, 2017 AT 10:02 AM (Merged)
Tiny
SJGRIMES56
  • MEMBER
  • 1998 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 181,000 MILES
Air Conditioning problem
1998 Chevy Silverado V8 Four Wheel Drive Automatic 181000 miles

Is there a possiblility that a heater control valve is sticking causing the A/C to get warmer at road speeds. My truck cools OK at an idle but on the road not as well. I've recently replaced the orifice tube and changed out the accumulator and vacuumed the system and charged it. But the problem persists.

Thanks.
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Friday, October 13th, 2017 AT 10:02 AM (Merged)
Tiny
MASTERTECHTIM
  • MEMBER
Thats a odd problem, usually its the other way around. You can try bypassing the heater valve and see if that does it but I have never seen that before. This is usually a indication of a condenser not cooling properly. Have you seen a abnormal rise in coolant temp on expressway? Can you tell me what the low and high side pressures are at idle? If you have a hand held set of gauges you might want to tape it to the windshield and watch the pressures when your driving and you lose cooling and tell me those pressures too if possible. I dont want to overlook the obvious but your sure the orifice tube went in the correct direction? I have installed them backwards before. Let us know, we have a bunch of good techs here and we should be able to get to the bottom of this.
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Friday, October 13th, 2017 AT 10:02 AM (Merged)
Tiny
STEVEHOYER
  • MEMBER
  • 1998 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 115,000 MILES
Air Conditioning problem
1998 Chevy Silverado V8 Four Wheel Drive Automatic 115000 miles

My A/C quit working. The fuses appear to be fine but there's no voltage at the connection to the compressor.

Is there an intermediate relay or something similar that is causing this?

Thanks
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Friday, October 13th, 2017 AT 10:02 AM (Merged)
Tiny
MASTERTECHTIM
  • MEMBER
Most likely you are out of freon. Try jumping the switch located on the receiver dryer(looks like a silver football) if the compressor comes on then either the switch is bad or your out of freon. Most likely out of freon.
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Friday, October 13th, 2017 AT 10:02 AM (Merged)

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