A/C Compressor not kicking on - The 1947 - Present Chevrolet & GMC Truck Message Board Network

alee75681 · 03-20-2007, 03:03 PM

I've done a lot of work to the interior of the truck, and recently also installed a new intake, carb, etc. while removing emissions stuff. Had the dash apart and put back together. Now the A/C compressor won't kick on. Blower and all vacuum operated vent functions seem to work fine. Compressor is plugged up and grounded as before. I feel like I might have knocked a wire loose under the dash. Can you guys give me places to look for connections or other advice?

Thanks!

Eyegore · 03-20-2007, 04:12 PM

Get a contnuity (sp?) tester and see if you have power after the switch is on.

piecesparts · 03-20-2007, 05:19 PM

Try jumpering the pressure switch on the accumulator. This is done by unplugging the rubber connector and putting a jumper wire into the two contacts. The switch will keep the A/C from working, because your freon charge may be low.

alee75681 · 03-23-2007, 10:01 PM

Pressure switch jump worked. I guess I'm low on freon. What are you guys using in your R-12 A/C units? Is there an alternative to converting to 134A?

piecesparts · 03-23-2007, 11:47 PM

There are alternative freons such as R12A, which is a deriviative that is made from mixed gasses. It supposed to be able to mix with R-12, but it would work best if the gas was completely removed and then replaced.

**WorkinLonghorn** · 03-24-2007, 01:10 AM

I get "Freeze-12" At the local Pep Boys and it works great in my R-12 system. Find the leak with the ffirst can,usually just an o-ring ( but could be a compressor seal) that you may be able to locate with the system running using soapy water sprayed on each connection.

87 STEPPER · 03-24-2007, 06:15 AM

Hold on there skippy!

First thing you need to do is see if you are in fact low on freon by hooking up some sort of pressure guages.

There are some cheapy ones you can get at any auto parts store on a single hose that will tell you the level of charge.

It could be a bad pressure switch and not the charge at all and a switch is gonna be cheaper than a lot of freon you may not need.

grinch4om · 03-24-2007, 08:17 AM

amen stepper! diagnostic flow charts are very important, suspect the cause and prove it. determine cause and effect. I've heard so many people throw parts at their trucks and luck into the fix. not saying any of the afore mentioned advise is wrong just that it is hard to pipoint without checking all components involved.

alee75681 · 03-25-2007, 01:20 AM

Thanks, guys. My dad is a mechanic and has a set of gauges that we will definitely use to check freon level first. We had already discussed that it might be a bad switch as well. Sorry I didn't mention that.

He also mentioned the Freeze12. I was just soliciting other opinions/experiences on the subject.

Thanks for the input!

03-20-2007, 03:03 PM	#1
alee75681 Registered User Join Date: Dec 2006 Location: Henderson, TX Posts: 19	A/C Compressor not kicking on I've done a lot of work to the interior of the truck, and recently also installed a new intake, carb, etc. while removing emissions stuff. Had the dash apart and put back together. Now the A/C compressor won't kick on. Blower and all vacuum operated vent functions seem to work fine. Compressor is plugged up and grounded as before. I feel like I might have knocked a wire loose under the dash. Can you guys give me places to look for connections or other advice? Thanks! __________________ Andy Lee Henderson, TX 1955 Belair 4 dr. Sedan (since 1984) Andy's 55 Cardomain Site 1984 SWB Fleetside (since 11/06)

03-20-2007, 04:12 PM	#2
Eyegore What Hump? Join Date: Apr 2003 Location: New River AZ Posts: 2,009	Re: A/C Compressor not kicking on Get a contnuity (sp?) tester and see if you have power after the switch is on. __________________ Lil red 86 c-10 99 Sub 78 Camper Special w/ 454

03-20-2007, 05:19 PM	#3
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: A/C Compressor not kicking on Try jumpering the pressure switch on the accumulator. This is done by unplugging the rubber connector and putting a jumper wire into the two contacts. The switch will keep the A/C from working, because your freon charge may be low. Last edited by piecesparts; 03-20-2007 at 05:20 PM.

03-23-2007, 10:01 PM	#4
alee75681 Registered User Join Date: Dec 2006 Location: Henderson, TX Posts: 19	Re: A/C Compressor not kicking on Pressure switch jump worked. I guess I'm low on freon. What are you guys using in your R-12 A/C units? Is there an alternative to converting to 134A? __________________ Andy Lee Henderson, TX 1955 Belair 4 dr. Sedan (since 1984) Andy's 55 Cardomain Site 1984 SWB Fleetside (since 11/06)

03-23-2007, 11:47 PM	#5
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: A/C Compressor not kicking on There are alternative freons such as R12A, which is a deriviative that is made from mixed gasses. It supposed to be able to mix with R-12, but it would work best if the gas was completely removed and then replaced.

03-24-2007, 01:10 AM	#6
WorkinLonghorn Senior Member Join Date: Dec 2006 Location: Studio City, Calif. Posts: 2,881	Re: A/C Compressor not kicking on I get "Freeze-12" At the local Pep Boys and it works great in my R-12 system. Find the leak with the ffirst can,usually just an o-ring ( but could be a compressor seal) that you may be able to locate with the system running using soapy water sprayed on each connection. __________________ '69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, stereo speakers, 2nd owner, Work-Truck supreme.

03-24-2007, 06:15 AM	#7
87 STEPPER STILL PLAYS WITH TRUX Join Date: Nov 2002 Location: Melbourne, Fla. Posts: 2,764	Re: A/C Compressor not kicking on Hold on there skippy! First thing you need to do is see if you are in fact low on freon by hooking up some sort of pressure guages. There are some cheapy ones you can get at any auto parts store on a single hose that will tell you the level of charge. It could be a bad pressure switch and not the charge at all and a switch is gonna be cheaper than a lot of freon you may not need. __________________ ~~Bruce~~ MY 87 STEPPER MY 99 2D/WD TAHOE

03-24-2007, 08:17 AM	#8
grinch4om dang its hot Join Date: Nov 2006 Location: frankfort kentucky Posts: 1,349	Re: A/C Compressor not kicking on amen stepper! diagnostic flow charts are very important, suspect the cause and prove it. determine cause and effect. I've heard so many people throw parts at their trucks and luck into the fix. not saying any of the afore mentioned advise is wrong just that it is hard to pipoint without checking all components involved.

03-25-2007, 01:20 AM	#9
alee75681 Registered User Join Date: Dec 2006 Location: Henderson, TX Posts: 19	Re: A/C Compressor not kicking on Thanks, guys. My dad is a mechanic and has a set of gauges that we will definitely use to check freon level first. We had already discussed that it might be a bad switch as well. Sorry I didn't mention that. He also mentioned the Freeze12. I was just soliciting other opinions/experiences on the subject. Thanks for the input! __________________ Andy Lee Henderson, TX 1955 Belair 4 dr. Sedan (since 1984) Andy's 55 Cardomain Site 1984 SWB Fleetside (since 11/06)



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