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#1
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HELP! A/C Compressor Won't Stop!!!!
Little Background...
1995 1.5L Civic DX 4-dr, purchased in November. Finally gotten around to repair the A/C Compressor this past weekend (money issues). The "original?" A/C Compressor housing was cracked and and I could literally see in. Anyhow we removed the old one and plopped in a refurbished one (yes I put a new dryer in as well). We flushed it with the flushing liquid (and a stupid $69 bottle and hose to flush it out with! grrr.), and did what the Chilton manual said to do. Turn the A/C on Max Cool and A/C on and start the car and we began to fill the system. Here is my dilemma. 1) now the that coolant is charged (high side reading 225 psi, low side about 40 psi) and system cooling nicely, I go to shut off the A/C from the dashboard control - the compressor clutch is still engaged! 2) pressure builds to over 400 psi (yikes)! I have to quickly shut the car off, or turn the A/C Blower back on to get the condenser fan to turn on and lower the pressure. .... <sigh> .... 3) I turn the car off, and start it up again -- the clutch is disengaged for a second while the car goes to idle speed, then it engages. I took the two relays (condenser fan relay and compressor clutch relay) apart so I could view them in action. The relays come on (and off) when the compressor comes on and off. 4) the compressor relay seems to be controlled by the ECM A15(?) line, which makes sense in the start up of the A/C after the engine has come on. 5) the compressor will "compress" even if the following conditions exist - low pressure switch open (system empty) or closed (system charged with new 134a) - A/C button is off at engine start - Blower is off at engine start - A/C button is turned off while engine running - Blower if turned off while engine running The thermal overload seems to be ok. The little diode "seems" to be ok - I haven't fully verified, but I believe that is more crucial for the condenser fan The compressor will stop if I disconnect the red wire connector to it. The red wire reads 0v while engine is started, 12v 1 or 2 sec after engine starts The only way I could prevent the compressor from running is to remove the 20A fuse in the U/H F/B for the Condenser fan/Compressor clutch. -------------- I wonder if this is how the first compressor housing was cracked and disintegrated when I bought the car - the compressor started to run and build up pressure without the condenser fan and built up pressure to past breakage... Do I have a bad ECM module? Is there a bad sensor? What do I check to get it to cycle properly (which it won't) and shut off when I turn the dashboard A/C controls off? The A/C light comes on and off when I press the dashboard button - but it seems to have no effect on the Compressor Clutch. Desperately seeking advice. Thanks in advance! ~lum |
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#2
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HELP! A/C Compressor Won't Stop!!!!
Is it possible the previous owner hot wired the compressor? I would be
looking for a jumper wire in one of the fuse/relay boxes. I would also look at the relays in the electrial box under the hood.... Test those relays. Good luck! |
#3
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HELP! A/C Compressor Won't Stop!!!!
Did you remember to pump all the air out of the system using a vacuum pump?
I ask because you didn't mention that part. Some people try to purge the air using refrigerant, but it doesn't really work. Air is compressible but does not liquify and interferes with the refrigeration process. It sounds as if you have an electrical fault, such as the compressor being hot wired, a relay being stuck, or maybe even a bad computer. How much of a wiring diagram does that Chilton's have in it? Earle "Lumkichi" > wrote in message ups.com... > Little Background... > > 1995 1.5L Civic DX 4-dr, purchased in November. Finally gotten around > to repair the A/C Compressor this past weekend (money issues). The > "original?" A/C Compressor housing was cracked and and I could > literally see in. > > Anyhow we removed the old one and plopped in a refurbished one (yes I > put a new dryer in as well). We flushed it with the flushing liquid > (and a stupid $69 bottle and hose to flush it out with! grrr.), and did > what the Chilton manual said to do. Turn the A/C on Max Cool and A/C on > and start the car and we began to fill the system. > > Here is my dilemma. > > 1) now the that coolant is charged (high side reading 225 psi, low side > about 40 psi) and system cooling nicely, I go to shut off the A/C from > the dashboard control - the compressor clutch is still engaged! > 2) pressure builds to over 400 psi (yikes)! I have to quickly shut the > car off, or turn the A/C Blower back on to get the condenser fan to > turn on and lower the pressure. > ... > <sigh> > ... > 3) I turn the car off, and start it up again -- the clutch is > disengaged for a second while the car goes to idle speed, then it > engages. I took the two relays (condenser fan relay and compressor > clutch relay) apart so I could view them in action. The relays come on > (and off) when the compressor comes on and off. > 4) the compressor relay seems to be controlled by the ECM A15(?) line, > which makes sense in the start up of the A/C after the engine has come > on. > 5) the compressor will "compress" even if the following conditions > exist > - low pressure switch open (system empty) or closed (system charged > with new 134a) > - A/C button is off at engine start > - Blower is off at engine start > - A/C button is turned off while engine running > - Blower if turned off while engine running > > The thermal overload seems to be ok. > The little diode "seems" to be ok - I haven't fully verified, but I > believe that is more crucial for the condenser fan > The compressor will stop if I disconnect the red wire connector to it. > The red wire reads 0v while engine is started, 12v 1 or 2 sec after > engine starts > > The only way I could prevent the compressor from running is to remove > the 20A fuse in the U/H F/B for the Condenser fan/Compressor clutch. > > -------------- > > I wonder if this is how the first compressor housing was cracked and > disintegrated when I bought the car - the compressor started to run and > build up pressure without the condenser fan and built up pressure to > past breakage... > > Do I have a bad ECM module? Is there a bad sensor? What do I check to > get it to cycle properly (which it won't) and shut off when I turn the > dashboard A/C controls off? > > The A/C light comes on and off when I press the dashboard button - but > it seems to have no effect on the Compressor Clutch. > > Desperately seeking advice. > > Thanks in advance! > > ~lum > |
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