99ImprezaOSport Posted June 28, 2009 Share Posted June 28, 2009 OK, I had great air conditioning until the end of last year. Well with temps on the rise it's time to get this fixed. The AC clutch does not engage even when system is charged. Should I be getting some charge (electric) to the AC compressor connectors? or is this controlled by something else? I read somewhere that there is odd problem with the connection with the ECU, causing the AC to not engage? Anyone know about this? which pins to check? Quote Link to comment Share on other sites More sharing options...
Scoobywagon Posted June 28, 2009 Share Posted June 28, 2009 First thing to check is the fuse for the A/C. After that, make sure that there's power at the the low pressure switch. If there is, then make sure that you get power up to the Compressor's clutch. If there's power there, but the clutch still doesn't go, then check the gap on the clutch. It may just be worn too far and the magnet can't engage. Quote Link to comment Share on other sites More sharing options...
99ImprezaOSport Posted June 28, 2009 Author Share Posted June 28, 2009 Fuses checked, where is the low pressure switch? I also read about "jumping" the clutch by placing a jumper from the battery to the clutch, should I need to place a fuse in the jumper? Quote Link to comment Share on other sites More sharing options...
Scoobywagon Posted June 28, 2009 Share Posted June 28, 2009 The low pressure switch is usually in the low side somewhere near the compressor. Though as I think about it, some of these cars put the switch in or near the expansion valve. I'd have to look it up. Can't remember right off hand. If you feel the need to test the clutch, yes, you can just run a jumper to the battery. I would NOT recommend running it that way. If, for some reason, you feel it necessary to run the a/c clutch that way, then yes....you DEFINITELY need a fuse. Now, I'm going to ask the obvious question...how have you determined that you have a full charge in there? Quote Link to comment Share on other sites More sharing options...
99ImprezaOSport Posted June 28, 2009 Author Share Posted June 28, 2009 Here is what I noticed / checked ... still scratching my head I jumped the compressor clutch running low under 25 L side added 3/4 can of 134a running 40-45 A/C cold I disconnected the jumper, reconnected the single clutch wire. Miracles, the clutch kicked in, everything is looking fine. I checked for leaks, nothing. I turned off the car & back on, started the A/C nothing. I jumped the clutch again, L side 40-45 as before, A/C cold. Reconnected the single wire clutch nothing. I figured I could run a couple wires and place a toggle switch inside but don't know what problems that might cause... Do both fans always kick on or only with A/C? Quote Link to comment Share on other sites More sharing options...
eppoh Posted June 29, 2009 Share Posted June 29, 2009 Sounds like a weak clutch solenoid or possibly low current flow to the clutch. Check the wire as much as you can and also the connection., Maybe wire pinched somewhere or connection corroded. Quote Link to comment Share on other sites More sharing options...
ScottG Posted June 29, 2009 Share Posted June 29, 2009 Do both fans always kick on or only with A/C? YES! Both fans are needed to provide proper airflow over the condensor. The fans are controlled by a pressure switch on the filter/drier (fastened to the passenger side strut tower). It's got the high pressure line running to & from it. In my experience, I've not seen a separate pressure switch controlling the compressor clutch, though there may be one built into the compressor. The only separate pressure switch in the system (that I know of) is the one on the top of the filter/drier - and that only controls the 2 fans. If the fans don't run, that shuts the system down because it can't get rid of its heat. If both fans aren't kicking in, try removing the plug from the filter/drier & jumping it. If that solves the problem, there may be a problem wth the pressure switch in the filter/drier. Hope this helps Keep Kool ScottG Quote Link to comment Share on other sites More sharing options...
Scoobywagon Posted June 29, 2009 Share Posted June 29, 2009 I disconnected the jumper, reconnected the single clutch wire. Miracles, the clutch kicked in, everything is looking fine. I checked for leaks, nothing. I turned off the car & back on, started the A/C nothing. I jumped the clutch again, L side 40-45 as before, A/C cold. Reconnected the single wire clutch nothing. Check the underhood relays. Sounds like one of them may be shot. Quote Link to comment Share on other sites More sharing options...
OB99W Posted June 30, 2009 Share Posted June 30, 2009 Quote Link to comment Share on other sites More sharing options...
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