Naxcar

FIXED!!!!
Thanks to all for the insight. I hope it helps more people.
BTW> Price for the part went up to $32.79 I went with standard ground shipping and got it in a day and a half. Installation was cake and only took about 20 mins.
Also known by ACDELCO part # pt1825

maddog5461

UPDATE! MY problem turned out to be the FAN RELAY. It wasn't staying connected, and would cycle on and off, when it should have stayed ON at all times when the AC is on. The ONLY reason I figured this out, is the relay finally went TOTALLY out, and my car overheated. Replaced the Fan relay, and AC problem was FIXED! Not sure what others are referring to about a bad connector. Laterz, Len P

Mikero

2002 Cavalier AC stopped working suddenly. I tried several possible fixes: New Pressure Transducer, Evacuate/Recharge, AC Clutch Relay, Check both Fuses(10A AC Clutch and 10A ERLS Fuses). Nothing worked. Then I GOOGLED the AC Problem and found out the 3 wire connector and wires to the pressure transducer/switch have a history of breaking inside the connector due to a very short and stressed factory wiring at the connector. (This Thread as a matter of fact.....) I disconnected the 3 pin connector and OHMED out the pins that go to the wire harness. I did not get any conductance i.e. infinity ohms (open circuit) between any 2. I pulled slightly on each wire (GREEN BLACK RED) and they pulled easily out. BROKEN. Called Chevrolet and they had a new connector and lead set for $68 dollars. Part 88988301 or PT825. YIKES!!! Went to local auto parts dealer, got out connector book by STANDARD (Part S619) and found the same connector for $25 dollars in stock but only difference is colors. Matched correct leads harness to new connector. Slid shrink tube on each wire then soldered corresponding wires together. The new connector and wires will add a good 4 inches to the length of the connection so be sue to tie up the slack so does not get caught on some moving items. Be sure to let enough slack so there is no stress on connector or sensor. Surprise! Connected and worked perfectly. Keep in mind that when I ohmed out the new connector I got a hi K reading of conductance betweem wires showing a good connection to the control module (PCM or ECU). HOPE SOMEONE CAN USE THIS INFO.

IBNFE

Great info everyone! I see a couple different fixes and not exactly sure if it's the same problem for all. My rpm surges when I'm stopped with it either in drive/reverse/neutral/park only when the a/c is turned on. Driving down the road all works fine with a/c on or off. A/C is charged properly. Also my engine cooling fan does not turn on at all, checked my fan relay and the fuse both were good, verified relay with the one next to it which is the same part number for the heater blower. I don't want to throw parts/money/time at the car (which no one does) so just looking to clarify what fixed the problem. I'm not sure if Mikero's connector and wire will fix mine or Maddog's fan relay would fix it.
BTW it's a 1999 Cav.
Thanks

atvrcr500

HI all I have been reading your thread. I have a 2002 cavalier and was having the same problems. But I could jump the relays and the fan and clutch would engage. Chevy dealer has replaced the compressor, evap, orfice valve, high pressure switch and now they are saying the ground portion of the PCM is bad.
From what I have read is the connector is bad and it is a chevy TSB. Am I correct on what I am reading?
Right now I am waiting for a new PCM to arrive so they can install it. Once I finally get it back I will look at the connector is there anything I need to look at specific?
Thanks for any help on this as I am not always home so it ends up at the dealer getting worked on while I am deployed

Mikero

Hi: Since the AC pump runs when you force power to it by jumping the relay, I suspect the sensor or sensor circuit. There should be a LOW/HIGH refregerant level sensor. If the refgt. R34 is low, then the sensor will signal the ECU(PCM?) to disallow the compressor to activate in order to save the compressor. That sensor is located in a difficult spot and is near the right front of the engine on one of the coolant lines. It has 3 wires connected to it as it is actually a pressure transducer. A transducer sends a analog signal to the ECU rather than a ON/OFF signal. Testing the ECU and transducer is relativley simple. First, CAREFULLY disconnect the connector at the sensor. You will need to use a small screwdriver to hold back the retainer clip on the sensor connecor. This should be self evident. Using a quality digital OHM meter and the engine and key off take an OHM reading between each pin on both the sensor unit and the connector from the ECU. You should get some type of reading. You will need to use a paper clip size wire to get the probe to connect to the femal side of the circuit. Not sure the ohm numbers but what you are checking for is continuity of wires and of the sensor. I got an OPEN circuit when I checked the ECU connector between each wire and between each wire and ground even though the wires appeared to be just fine from the outside. That indicated a break in the wire. Since the connector wire is actually too short from the factory, it puts tension on it and breaks the wire over time. You can get a repair kit from CHEVROLET for 70 dollars which is a connector, crimp splices and shrink tubine. OR you can go to a quality auto dealer or Google STANDARD S619 (It is a typical throttle body style connector) and get the same connector minus the splice items and has different colored wires for about 15 dollars. If you go the 15 dollar way, make sure you connect the original ECU wires to the exact same pins as the old connector was wired. Disregard the colors on the new connector as they will not match up. I took my car, first, to a professional AC shop. They were stumped. I went to this forum and discovered the connector issue. Sure enogh, that was it. Just a note: I purchased a ECU off eBay for the car and that did not fix it that is before I discovered the sensor wire problem. I am still running the eBay ECU with not troubles. Do not pay 500 dollars for a ECU from the dealer. Most shops are a black box replacement and try fix it. It takes a skilled person to track down and test wireing. You can do it. Hope this helps. You can remove the sensor by disconnecting the wireing, then unscrewing it out of the refg. tubing. There is a shrader valve and it will stop the coolant from leaking out when you unscrew the sensor. Brilliant engineering!

atvrcr500

Thanks for the info, finally got the PCM to start the car and still having the compressor issue. The high pressure switch has already been replaced before any of the other parts were changed. R134 reading are where they are suppose to be for a non running compressor. I have ordered the connector and figure I will go down about an inch and a half before I cut the old connector off. I am hoping this will do it. I did notice that there is suppose to be 5 volts on one of the wires so before i will cut the wires to see if it is getting the voltage required.
This has been a big trial and error and I wished I would have found this site before doing the PCM it might of saved me a couple hunderd from the local part house.
Will post up what i finally find.
Once again thanks for the help
Don

in2pro

Thank you for your service, and thank you for following up on what works and doesn't as that is what makes this forum work...

atvrcr500

I can rest easy tonight Replaced the Hi pressure switch connector and vavoom!!!! it works. I am so happy I will not be messing with the dealership for a while now. Well I can say is THANK YOU to the forum. The local dealership had no F***ing clue as to the problem all they would say is it is the compressor because it was not a Delphi.
The orginall one had blown the relief valve in the back when the hi pressure switch stopped working so I did need to replace the compressor, dryer and orfice. But when the dealer kept wanting to sell me a PCM I went to looking............ Yes I did buy the PCM and I truly do believe it was not the problem.
The problem was the wires to the high pressure switch. Yes I gave it more room and have wired tied it so it can not get into the belt.
Thanks again for everyone's help.
Have a great weekend and I will enjoy my drill weekend LOL

atvrcr500

One more note after driving the cav tonight. Before all this parts the Cav would idle extremly bad regardless if the air was on or off. I have read several different areas about rough idle. I had replaced the coils, wires plugs and even the modules under the coils and was told it was the trottle body needing cleaned.
Well guess what I believe the new PCM or at least the flash that was put in the PCM solved the idle problem as well.

Folks I hope all feel this info useful.