a/c help
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Joined: Mar 2011
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From: Valencia CA
a/c help
I'm looking at trying to fix the a/c in my '75 Vette. It was converted to 134A at some point in its life, but the guy I bought it from didn't know much about it. It was working when he got it, but it "burned out". So he had it unplugged.
So I've got a couple of questions:
1) The plug that goes on the compressor was burnt/melted. Basically, it crumbled to pieces when I tried to plug it back in. What would cause that plug to melt?
2) Should I be getting 12v at that plug? (assuming that I've turned the a/c on)
Thanks!
So I've got a couple of questions:
1) The plug that goes on the compressor was burnt/melted. Basically, it crumbled to pieces when I tried to plug it back in. What would cause that plug to melt?
2) Should I be getting 12v at that plug? (assuming that I've turned the a/c on)
Thanks!
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Joined: Mar 2011
Posts: 66
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From: Valencia CA
Fuse is correct.
I'm not getting 12v to the plug.
The pulley on the compressor spins freely, but since there is no power to it, I don't know if it is frozen internally.
So I'm guessing that either the refigerant leaked out, or the pressure switch is bad. So next I'll check to see what the PSI is. If there is 56 PSI or better, the switch is probably bad. If the pressure is low, I could just have it charged and see if everything works... but I don't want to spend the money charging it if the compressor is bad. So I want to check the compressor to make sure it isn't toast. Is there an easy way to check the compressor? I could check for continuity between the terminals to see if it shorted internally. If it isn't shorted, could I run 12v directly to it to see if the clutch engages?
Any other thoughts would be great!
Thanks!
I'm not getting 12v to the plug.
The pulley on the compressor spins freely, but since there is no power to it, I don't know if it is frozen internally.
So I'm guessing that either the refigerant leaked out, or the pressure switch is bad. So next I'll check to see what the PSI is. If there is 56 PSI or better, the switch is probably bad. If the pressure is low, I could just have it charged and see if everything works... but I don't want to spend the money charging it if the compressor is bad. So I want to check the compressor to make sure it isn't toast. Is there an easy way to check the compressor? I could check for continuity between the terminals to see if it shorted internally. If it isn't shorted, could I run 12v directly to it to see if the clutch engages?
Any other thoughts would be great!
Thanks!
Instructor
Joined: Apr 2011
Posts: 167
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From: Jacksonville Florida
12v straight to the compressor terminals will engage the clutch. You will see and hear the front of the clutch pull in to the compressor. You can do that without the engine running. If the belt is off the pulley then you can try to turn it when it is engaged. It won't spin freely like when it is disengaged. I don't know how difficult it is to turn the the compressor but it think they are pretty tight. If anyone knows please share.
-Rick
-Rick
Instructor
Joined: Oct 2010
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Rick,
When I did the trouble shooting on mine I jumped the pressure switch, the compressor engaged so my problem was low freon. Do not leave the jumper on to long as this may damage the pump. When I went to add freon I noticed a leak on the pump housing, after flushing the system I replaced the pump, drier, all the O-rings and Orfices filter vacuumed the system out and added freon as was good to go. The clutch on the new pump was a little difficult to turn, Oh I almost forgot don't forget to add oil. If I had it to do all over again I would have a professional flush the system. Hope this helps.
Ron
When I did the trouble shooting on mine I jumped the pressure switch, the compressor engaged so my problem was low freon. Do not leave the jumper on to long as this may damage the pump. When I went to add freon I noticed a leak on the pump housing, after flushing the system I replaced the pump, drier, all the O-rings and Orfices filter vacuumed the system out and added freon as was good to go. The clutch on the new pump was a little difficult to turn, Oh I almost forgot don't forget to add oil. If I had it to do all over again I would have a professional flush the system. Hope this helps.
Ron
Last edited by rbowman; Aug 25, 2012 at 09:35 AM.
