Help! Neon A/C compressor problems.

[dovecs]

Hi all,

I have a 97 SOHC with A/C. Recently, the AC compressor stopped working (ie, clutch does not engage). I know the pressure is OK in the system.

When I turn the A/C on from the dash, both electric radiator fans activate, but no compressor clutch. I tried shorting out the pressure switch, this also did not cause the compressor clutch to engage.

I am noticing this compressor has two electrical connectors attached to it. The front connector (closest to the pulley) I assume is power to the clutch. My big question is this: what is the function of other connector (on top on the compressor)?

While troubleshooting, I uplugged the top connector from the compressor, and put my voltmeter across the pins (coming from the car harness). When the car is running, and the A/C in the 'off' position, I measure 0 volts here, but when I turn the A/C switch 'on', I am measuring +12V here, I assume this is OK?

Also, what controls the signal to the clutch connector? What voltage(s) should I be looking for here?

BTW, I have checked all fuses, also tried swapping the A/C clutch relay, no help there either.

Thanks in advance,

Hot in Nevada :VHOT:

[dodgeneonACR98]

Im going to take a poke at this and say it's your compressor it's self. Im not an expert but if everything you tried didn't get it to kick on Id say it's toast Bro. Keep us posted on it!

[RaminMD]

Hey brother, I am having the SAME problem. I thought it was my compressor and put a new one in. Please keep me updated on what you find and I will update you with any new info. Thanks!

[Rick99]

New compressor? Don't throw money at the problem! If you have 0-volts at the clutch coil and 12volts at the high pressure switch, replace the high pressure switch (it has a schrader valve, so you can unscrew it and screw on a new one.)

[dovecs]

Hi RaminMD,

My buddy is supposed to get me the (detailed) electrical drawings for this system. I am suspecting my problem is the high pressure switch (I suspect this is the GREEN connector which is part of the compressor manifold, the part that has the 'high' and 'low' side lines attached. I noticed that if you purchase a rebuilt, the manifold does not come with the unit, so you have to swap out your old manifold, is that what you did? If so, the switch could be bad. I will post more when I get this working. :cool:

[dovecs]

It's Fixed, PTL!

So, here's the saga, beginning to end:

My daughter and I bought her (97) Neon about 8 months ago. The car was immaculate, but at that time, I noticed the A/C was cutting in and out, and asked the seller about this. He showed me where the problem was (or so he THOUGHT), he showed me that by 'wiggling' A/C high pressure switch connector would make the A/C function OK, so, I thought, no problem, I'll just fix that myself, and we went ahead and bought the car. He actually had the suspect connector tie-wrapped to one side, in order to put tension on the wires, in an effort to get the A/C to work consistently (I probably would have done the same thing).

As it turns out, and through much prayer and troubleshooting, the actual problem was a broken wire on the connector which goes to the A/C CLUTCH! Since these wires come from the same harness, the effect of wiggling on the A/C high pressure connector was actually causing the broken wire to make/break contact, until finally one day it broke off completely. It wasn't until my buddy recently got me the complete ALLPAR drawings on this system that I was able to start troubleshooting. After bypassing the Low Pressure and High Pressure switches, swapping relays, fuses, etc., did I really start looking closely, and there it was, hanging out in space, the broken wire.

Because the engine comaprtment is so tight, my fix is temporary, but I am sure it will last all summer, or at least until I feel more ambitious. I decided to cut mating wire from the harness on the other side of the connector, strip back this wire and the broken wire, and use a Pomona jumper to bridge the two together. Viola!

I hope this info helps someone else, I priced a new compressor, outrageous! I am glad now we didn't waste the money. BTW, on this vehicle, the high pressure switch (green connector) is not a shrader valve type, it you remove it, you must totally evacuate and recharge the system.

:gr_patrio