1997 A/C is intermitant…help requested.
Question:
I have a 1997 GMC Sierra with 350. I can go out and crank it up and the AC will blow ice cold, for a long as I am moving or do not shut either the AC or the engine off. If I shut it off an then turn it on again the AC will blow warm air and get progressively hotter. It does not matter if I only drive 1 mile or 100 miles. I thought it may be freezing up, but it was not. I thought it may be a bit low on freon, so I bought a recharghe cyclier of freon, but then I noticed when this sudden stoppagage of cold air occurs the compresser is not turning. I figured its got to be low on freon and the pressure switch is keeping it from running. I wait and catch the system when it is working and hook up the charge cylinder and gage, but the system shows sufficient freon, so that should eliminate low freon as a problem. When it does work its good and cold. I am at a loss.any ideas what to look for? Possibly a clogged dryer? Vehicle only has 50K on it. Taking it to a dealer is out of the question for now. Regards — Visit my website: http://www.frugalmachinist.com Contents: foundry and general metal working and lots of related projects. Regards Roy aka Chipmaker // Foxeye Opinions are strictly those of my wife….I have had no input whatsoever. Remove capital A from chipmAkr for correct email address
Response:
I just got finished with playing with this system. I too have come to the conclusion its the pressure switch. I can start up the AC watch the clutch on the compressor kick in, and everything works. Then it will click off, and just a jiggle of the plug on the LP cutoff switch is enough to get it going again. I also used a jumper and it will just keep runnning and running and running. Compressor etc all sound fine, but I did manage to add a small amount of freon, hope tht does not hurt anythng, but its getting super cold now, just like when new. MAybe it was a bit low, but I do honestly thnk its that switch on the accumulator. Thanks for your input Regards – Hide quoted text — Show quoted text – >x<>-I had a similar problem on my R-12 equipped 94 Jimmy. Replaced the >x<>-low pressure switch and it’s worked 100% of the time since I replaced >x<>-it, except when the fuel pump died. Part was around $20 at a dealer >x<>-and I was able to replace it myself without evacuating the freon. >x<>-Dunno if yours is the exact same thing, but it would be a cheap place >x<>-to start. Here’s a good test for the switch, when the system stops >x<>-working pull the plug and short the 2 contacts on the plug, not the >x<>-switch, with a piece of wire, if the compressor comes on, the switch >x<>-is bad. Mine was located in the accumulator, dunno if yours is the >x<>-same. >x<>- >x<>- >x<>->I have a 1997 GMC Sierra with 350. I can go out and crank it up and >x<>->the AC will blow ice cold, for a long as I am moving or do not shut >x<>->either the AC or the engine off. If I shut it off an then turn it on >x<>->again the AC will blow warm air and get progressively hotter. It does >x<>->not matter if I only drive 1 mile or 100 miles. I thought it may be >x<>->freezing up, but it was not. I thought it may be a bit low on freon, >x<>->so I bought a recharghe cyclier of freon, but then I noticed when this >x<>->sudden stoppagage of cold air occurs the compresser is not turning. I >x<>->figured its got to be low on freon and the pressure switch is keeping >x<>->it from running. I wait and catch the system when it is working and >x<>->hook up the charge cylinder and gage, but the system shows sufficient >x<>->freon, so that should eliminate low freon as a problem. >x<>-> >x<>->When it does work its good and cold. I am at a loss.any ideas what to >x<>->look for? Possibly a clogged dryer? Vehicle only has 50K on it. Taking >x<>->it to a dealer is out of the question for now. >x<>->Regards
– Visit my website: http://www.frugalmachinist.com Contents: foundry and general metal working and lots of related projects. Regards Roy aka Chipmaker // Foxeye Opinions are strictly those of my wife….I have had no input whatsoever. Remove capital A from chipmAkr for correct email address
Response:
I had a similar problem on my R-12 equipped 94 Jimmy. Replaced the low pressure switch and it’s worked 100% of the time since I replaced it, except when the fuel pump died. Part was around $20 at a dealer and I was able to replace it myself without evacuating the freon. Dunno if yours is the exact same thing, but it would be a cheap place to start. Here’s a good test for the switch, when the system stops working pull the plug and short the 2 contacts on the plug, not the switch, with a piece of wire, if the compressor comes on, the switch is bad. Mine was located in the accumulator, dunno if yours is the same. – Hide quoted text — Show quoted text ->I have a 1997 GMC Sierra with 350. I can go out and crank it up and >the AC will blow ice cold, for a long as I am moving or do not shut >either the AC or the engine off. If I shut it off an then turn it on >again the AC will blow warm air and get progressively hotter. It does >not matter if I only drive 1 mile or 100 miles. I thought it may be >freezing up, but it was not. I thought it may be a bit low on freon, >so I bought a recharghe cyclier of freon, but then I noticed when this >sudden stoppagage of cold air occurs the compresser is not turning. I >figured its got to be low on freon and the pressure switch is keeping >it from running. I wait and catch the system when it is working and >hook up the charge cylinder and gage, but the system shows sufficient >freon, so that should eliminate low freon as a problem. >When it does work its good and cold. I am at a loss.any ideas what to >look for? Possibly a clogged dryer? Vehicle only has 50K on it. Taking >it to a dealer is out of the question for now. >Regards
