GMT 800 & Older GM General Discussion 2006 & Older Trucks | General Discussion

A/C problems, need suggestions...

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Old Mar 13, 2012 | 05:28 PM
  #11  
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Originally Posted by Robert91RS
No, you really want to confirm voltage at the coil when possible.
I guess that would be the most effective way to test it, I just need to quit being lazy

Thanks for the help
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Old Mar 13, 2012 | 06:00 PM
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Let us know what you find and we will go from there.
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Old Mar 13, 2012 | 06:06 PM
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If it was working, but the clutch was cycling rapidly then i would check the charge on the system first.. it dosent take much refidgerant gone from the system to cause it to cycle rapidly/not work at all.
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Old Mar 13, 2012 | 09:58 PM
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He shorted the low pressure switch on the accumulator already though. Had a lack of freon been the problem, bridging those two terminals would have caused the clutch to engage.
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Old Mar 13, 2012 | 10:40 PM
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Do you have access to anything like a scan tool or even EFILive from a friend. With either you can force the compressor on and see if the clutch engages. These trucks are temperature sensitive as the system shuts down around probably 36 F or so, but being in Texas and needing A/C that will not be your problem lol.

Even have someone scan the headunit on the climate control for trouble codes. Mine has the Recirc door actuator code present all the time but the a/c still works as does recirc so I don't bother fixing it, lol.
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Old Mar 14, 2012 | 08:27 AM
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I'm going to see if Wheatley has time next week to scan it and command the compressor on. And hopefully this weekend, I get a set of loaner a/c gauges from O'Reilly's or AZ.
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Old Mar 15, 2012 | 10:03 PM
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Originally Posted by Robert91RS
He shorted the low pressure switch on the accumulator already though. Had a lack of freon been the problem, bridging those two terminals would have caused the clutch to engage.
Didnt catch that.. Id like to see what this turns out to be..
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Old Mar 16, 2012 | 11:57 AM
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I will post up with what I find out. Might be a couple of weeks, going to the rodeo this weekend and wedding next.
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Old Mar 22, 2012 | 12:24 PM
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So tested it with a multimeter after bridging the low pressure sensor pigtail and driving around until it was up to operating temp. No voltage coming from the pigtail going to the compressor. Tested the multimeter on other things, worked fine. Checked all of the compressor and HVAC related fuses and they all check out. What is the next step? Should I take a wire from the battery to the compressor to see if it fires up? What are the likely points of failure? Is there a way to test the a/c control panel inside the truck?

But there is no continuity from the low pressure sensor, so does that mean the system has low pressure?
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Old Mar 22, 2012 | 02:13 PM
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You are bridgeing the connector for the switch mounted on the accumulator right?(just want to verify) Also, does everything else seem to be operating properly? ie the lights on the a/c control head light up etc etc.
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