I have a 2001 Plym Neon. The Air Conditioning Compressor Clutch will not engage. When I sping the clutch with my hands it spins freely but when I switch on the A/C the clutch does not lock up to engage the compressor. It is a brand new compressor so I know that is not the problem. I also checked and replaced the A/C Clutch Relay and still nothing!
Can anyone please help me out on where to start looking next. I am going to start tracing out wiring diagrams tomorrow but I was hoping someone may have a direction for me to start looking. Thanks for your help everyone!!
Joe
rice_eater
04-29-2006, 10:32 PM
beats me... when you try and turn it on does it turn on briefly and click off, or never engage at all?
steven_shirey
04-29-2006, 10:54 PM
is the wire pluged in?
RaminMD
04-29-2006, 11:15 PM
It does not engage at all!
rice_eater
04-30-2006, 09:38 PM
does the engine rev up when you turn the dial to A/C? what happens when you select defrost? does the AC pump engage then or does the engine gain a few hundred rpms? It's sounding like a wiring problem to me... or the switch on the pump is toasted...
RaminMD
04-30-2006, 09:59 PM
Compressor is not kicking on at all, the Compressor is brand new along with the Clutch switch. Maybe it is the pigtail connector. I will have to see if this is the problem. It probably is a wiring issue.
rice_eater
04-30-2006, 10:07 PM
even if the compressor does not engage, when you turn the switch to the A/C position (or defrost) the engine should "float" up a few hundred rpm and hold on to revs when you let of the gas to shift/coast to a stopsign, etc... The PCM should detect the switch on, and compensate by adding more fuel (i.e. more power) to run the pump, even if is not engaging properly... I THINK.... I know when i had my AC/PS belt off, when i turned on defrost (engages AC pump) the engine would float/hold on to revs, but the pump was probably engaging, even if there was no belt to turn it and actually use extra power.... I guess we need to find out where the PCM reads the pump on/off.
Rick99
05-01-2006, 11:13 PM
I'd check the most likely thing first-- is there a refrigerant charge? The system has a low pressure cut-off switch and if you've lost all your refrigerant, the clutch will not engage at all. You can tell if there's a charge by attaching a gauge to the low pressure port, with the system off the pressure should read pretty close to ambient temperature. You can check this with a cheapo gauge that comes with one of those refill kits or with a complete manifold gauge set. If you want to do any A/C work, I suggest you buy the manifold set-- I've seen that at Harborfreight Tools for about $50, so they'll pay for themselves with the first repair job. Note that the pressure will not tell you how much refrigerant is in there, but it will tell you if refrigerant is in there. If there's no pressure, then you have a leak-- you have to find and fix the leak, then evacuate and recharge the system. If there is pressure and your compressor is not coming on at all, then it's likely you have an electrical problem. You can start by checking the fuse, then with the A/C switch on, check for voltage at the low pressure cutoff switch, the high pressure switch and finally the compressor clutch (you can work the other direction if you like) to isolate the problem. You could also have a faulty switch at the A/C control.
If there is pressure greater than about 35PSI in the system, but the refrigerant charge was just low, the clutch would cycle on and off periodically-- it doesn't sound like this is your case.
Good luck!
dovecs
05-09-2006, 08:53 PM
You can try bypassing the low pressure switch and/or the high pressure switches briefly, it it kicks on then, and blows cold, I would say you have a bad switch. If it kicks on, but is not so cold, the refrigerant charge is incorrect, have a shop check it. I would not advise leaving either of these switches bypassed for too long, you can ruin the compressor and/or other components that way (expen$ive), if in fact the switches are working properly, and the refrigerant level is incorrect. I did not notice you indicated you check the A/C fuse (under the hood on my 97, but maybe not for yours). Keep us posted when you get it fixed! :gr_patrio
