xtremerevolution Posted August 12, 2009 Report Share Posted August 12, 2009 My A/C usually works. Key word being "usually." Today I had to go to Hollywood for work, which basically consists of a ton of traffic and >80 degrees temperature. Its pretty disgusting to sit in that weather with the windows open, so I had my A/C on. I arrived at my client's location, finished my work, and got back to my car, and my A/C didn't work. Every time I'd turn it on, the engine would rev up slightly, and then fall back down, but no cool air. The A/C clutch was not engaging either. I had recently replaced the compressor relay as it would only work when you pushed it at an angle. I must have spent 20 minutes in the parking lot of a McDonald's messing around with the wires and the relay to try to figure out what the hell was wrong, and eventually gave up and tried to locate the nearest Auto Zone on my GPS. I finally found it, and half way to autozone (.3 miles away), the air started blowing ice cold, and its worked since then. Anyone have any ideas? Also to note, sometimes I'd be driving in stop and go traffic and turn the A/C on, and the engine would rev up and continue to rev higher and higher for 3-4 seconds, then it would fall back down and the A/C wouldn't turn on. this only happens when I'm at a stand still or moving very slowly. I would then try to turn the A/C on again, and sometimes it would work, and other times I'd need to shut down the car and start it up again to get it to work properly. What system is it that automatically revs the engine higher and creates that air sucking noise in order to allow the engine to run at a higher RPM while idling with the A/C on to prevent the engine from shutting down? I'm guessing there's something wrong with that, but I don't know enough about it to know where to start looking. Quote Link to comment Share on other sites More sharing options...
slick Posted August 12, 2009 Report Share Posted August 12, 2009 You sure it is an electrical issue and not the clutch starting to fail? Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted August 12, 2009 Author Report Share Posted August 12, 2009 You sure it is an electrical issue and not the clutch starting to fail? How long would it take for this clutch to fail? Its been doing this since I refilled the system 4 or so months ago. It just got more annoying now since its getting hot out. And no, I'm not sure. That could be it. This compressor has 80k miles on it, and was installed brand new by a dealer. Can one replace just the A/C compressor clutch? Edit: Nevermind, I answered my own question. It can be replaced...for $110 off of rockauto. Looks like this would have two wires going into it. Can one short those wires to manually engage the clutch? Quote Link to comment Share on other sites More sharing options...
slick Posted August 12, 2009 Report Share Posted August 12, 2009 I know you can do it in the fuse box. Pull the relay out to do this. Basically, the low pressure switch is what energizes this relay, and allows 12V+ to go down to the AC compressor. So, you will need to find the 12V+ and the lead that go's down to the compressor, and go from there. Speaking of which, hows the pressure in your system? If it is good, you could possibly be looking at a failing low pressure switch, or even a failing high pressure switch. Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted August 12, 2009 Author Report Share Posted August 12, 2009 I know you can do it in the fuse box. Pull the relay out to do this. Basically, the low pressure switch is what energizes this relay, and allows 12V+ to go down to the AC compressor. So, you will need to find the 12V+ and the lead that go's down to the compressor, and go from there. Speaking of which, hows the pressure in your system? If it is good, you could possibly be looking at a failing low pressure switch, or even a failing high pressure switch. Pressure on the line is good, right around 40 PSI. Quote Link to comment Share on other sites More sharing options...
Addicted To Boost Posted August 18, 2009 Report Share Posted August 18, 2009 Remove your compressor relay and jump the pins with a paperclip. Your compressor should fire up and continue to run until you remove the paperclip.. does it? Quote Link to comment Share on other sites More sharing options...
1990lumina Posted August 18, 2009 Report Share Posted August 18, 2009 The ECM is responsible for idling the motor hgiher. It uses the IAC motor to open more and idle the motor higher. Similar to the power steering switch. Quote Link to comment Share on other sites More sharing options...
digitaloutsider Posted August 18, 2009 Report Share Posted August 18, 2009 Sounds like your clutch is on the way out. Mine's a rebuilt unit with less than like 20k on it and it already has this problem. If I rev the motor or smack the clutch it engages. Quote Link to comment Share on other sites More sharing options...
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