A/C issues......

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May 25, 2009 | 03:42 AM

#31

Blue Rebel

Posting Guru

Joined: Jul 2004

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From: Cottage Grove, WI

Once you get the real guage set you will be able to tell. Find out what the low psi cut out switch cuts out at, and if your pressures are higher than that... bad guage.

May 25, 2009 | 07:08 AM

#32

subford

Fleet Owner

Joined: Aug 2005

Posts: 23,667

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From: Easton,Ks

Quote:

Originally Posted by Q in Sac

Now if I can't get any gauges, can I still jump the low pressure switch and refill without damaging something?

Yes you can jump the low pressure switch while charging without damaging anything.
The low pressure switch is a safety for the compressor when you are not working on the system.

Quote:

Originally Posted by Q in Sac

Is there a way to test if the low pressure switch is bad?

Sure, unplug it and use an ohm meter (or a battery powered test light with the battery inside of it). The system should be less than 24.5 PSI and the switch should be open, no light on the test light or infinity on the ohm meter.
Then when the pressure reaches 43.5 PSI the switch should snap closed and the light should light or the ohm meter should read near zero ohms.

If the pressure is already above 24.5 PSI and the switch is closed just unscrew it out of the Accumulator and it should snap open. You will not lose the charge when you unscrew it.

Do not forget to put 4 oz of PAG 46 oil extra in the system when you charge it if there is not a sticker on the system saying it has already been done. Or you may loose the compressor down the road.

May 25, 2009 | 10:38 AM

#33

Q in Sac

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Thanks for the info. I will test today and post my results.

May 25, 2009 | 11:45 AM

#34

Q in Sac

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Did the above, tested the switch. Got 0.00 reading. Then I disconnected it heard the click. Reinstalled, put the gauge back on, got a 0 reading. Started to refill it got up to 15-20 psi and emptyed the can. Need to get another 2 cans and I believe it will solve my A/C issues.

May 25, 2009 | 12:48 PM

#35

subford

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From: Easton,Ks

If you have zero ohms and the compressor clutch is not engaging then you have other electrical problems.

May 28, 2009 | 06:05 PM

#36

Q in Sac

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Well I fix my A/C issue. Faulty Low Pressure Switch. Went to the junkyard found a couple of 95-97 F-250 got the switches. Swapped out the old one. Compressor engaged, blowing cold air out the vents. Checked my low side pressure. 45 psi while compressor engaged. COLD AIR.