AC not working

Tiny
BTUGGLE
  • MEMBER
  • 1999 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 195,000 MILES
About a month ago, my compressor went out. I had it and the accumulator replaced. It cooled for a couple of weeks and now it will only cool for about five minutes. The compressor seams to not be turning on. I thought it was the clutch cycling switch on the accumulator, because I could remove the wiring harness and install a jumper and it would kick on. So I replaced the switch and now the compressor will not switch on. Once again, I tried the jumper, still nothing. I have a low pressure gauge and it is showing a reading of 65. Any answers would be greatly appreciated
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Monday, August 9th, 2010 AT 7:44 AM

33 Replies

Tiny
HMAC300
  • EXPERT
Take it back to where you had it repaired as it's not been a long time. it sounds as if they didn't do something right like didn't evacuate the system like it should have been and your unit is freezing up. It cools then warms then if you continue will cool again. Or there is a blockage in the orfice due to compressor failure, which means theys should have done a freon cleansing before replacing the part as little particles get int eh system and block the orfice.

This guide can help fix it

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

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Monday, August 9th, 2010 AT 9:12 AM
Tiny
BTUGGLE
  • MEMBER
They say they flushed the system out, but I will take it back to them. One thing I did notice yesterday when the compressor was kicking on and off, the gauge readings went from 35 to 65+ as it would kick on and off. When it quit working, the pressure reading remained at about 65.

Thanks for your help.
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Monday, August 9th, 2010 AT 10:20 AM
Tiny
HMAC300
  • EXPERT
35 is abotu right on the low side depending on the temperature outside when the compressor is on. But it still shouldn't stop cooling like you've said. There is definitely something wrong with it. I still thinkit's got a freezing up condition but that would take evacuate and recharge on the system and probably change the acumalator to keep it dry.
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Monday, August 9th, 2010 AT 5:14 PM
Tiny
BTUGGLE
  • MEMBER
I will not be able to take it back to the repair shop where I had the compressor and dryer replaced till next week. However, when I got home from work yesterday I decided I would evealuate it some more and discovered what felt like air blowing from evaporator tube where it connects at the entry to the cab. Could this leak be the possible problem?
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Friday, August 13th, 2010 AT 7:33 AM
Tiny
HMAC300
  • EXPERT
Sorry about being late with this as i've been away. The air blowing out is just air and unless it is a quite a bit which I doubt, it isn't causing the problem. That can be taken care of with what mechanics call dum-dum. From what you describe it still seems to me to be "freezing up" I have to beleive that it's the orfice is being blocked once in a while causing t eh problem. You migh tmention this to them, but hard telling what they will say. The orfice has a filter on it and it may be plugging then breaking loose and blocking again. I would take a look at it anyhow then try a pump down then a freon sweep and pump down again before refilling the system. That way the moisture that may have built up in the system should all be gone.
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Monday, August 16th, 2010 AT 1:22 PM
Tiny
BTUGGLE
  • MEMBER
Sorry, I know it has been a while since I have been on here. I finally took my truck back to the shop that replaced the compressor. System was full of freon and everything checked out except that non of the switches (high or low pressure) are getting any power to the them. The mechanic told me that it could be the circuit board in the dash. He is supposed to find a wiring diagram so tha we can check it out. O you have any ideas of what it could be? Thanks!
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Thursday, October 14th, 2010 AT 10:08 AM
Tiny
HMAC300
  • EXPERT
I am taking it that this is a 5.3L and you have the basic a/c. In the underhood bec there are fuses and a relay that go to the compressor. these could be a blown fuse, a relay not working or not getting a good connection there as well as the computer.... i'm sending the basic wire diagram along on here. I think you should be able to enlarge it , if not print it for sure and then enlarge it...


http://www.2carpros.com/forum/automotive_pictures/406719_ac_1999_1.jpg

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Thursday, October 14th, 2010 AT 2:47 PM
Tiny
BTUGGLE
  • MEMBER
Thank you so much, will check out this weekend.
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Friday, October 15th, 2010 AT 6:45 AM
Tiny
JOEDOYLE
  • MEMBER
  • 1999 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 102,000 MILES
I just got done charging my 99 Silverado with r-134a in the low side service port. Now, when I turn the AC all of the way up the truck seems like it wants to die every 10 seconds or so. This happened immediately after I charged the AC, I let it run for about 5 minutes after and still same problem. I am going to stop using the AC until I get a response. When I turn the AC off the truck runs fine. Can anybody tell me what went wrong? I used the right coolant and put it in the right spot. I think.
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Friday, June 26th, 2020 AT 11:39 AM (Merged)
Tiny
MHPAUTOS
  • EXPERT
Hi there,

Thank you for the donation,

Did you use are re charging manifold with hi & low pressure gauges, I feel that you may either have a faulty compressor ( pressure leaking from hi to low) or the system is way over charged, have the system pressures check by a A/C tech this will be the first thing that you should do)

mark (mhpautos)
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Friday, June 26th, 2020 AT 11:39 AM (Merged)
Tiny
JOEDOYLE
  • MEMBER
No, I didnt use any guages. The guy at the auto store sold me a can of r-134a with a valve that connects to the low end. Between his instructions and the instructions on the can I was told to use the entire can. The can leaked as I put it in (at the valve), maybe I used too much?
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Friday, June 26th, 2020 AT 11:39 AM (Merged)
Tiny
STEVEHOYER
  • MEMBER
  • 1998 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 115,000 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, June 26th, 2020 AT 11:40 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, June 26th, 2020 AT 11:40 AM (Merged)
Tiny
SJGRIMES56
  • MEMBER
  • 1998 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 181,000 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, June 26th, 2020 AT 11:40 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, June 26th, 2020 AT 11:40 AM (Merged)
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, June 26th, 2020 AT 11:40 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, June 26th, 2020 AT 11:40 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, June 26th, 2020 AT 11:40 AM (Merged)
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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Friday, June 26th, 2020 AT 11:40 AM (Merged)
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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Friday, June 26th, 2020 AT 11:40 AM (Merged)

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