snappytee Posted January 22, 2013 Report Share Posted January 22, 2013 I never have seen this issue before. I was wondering if anyone out there knows something I can try. The AC compressor runs all of the time after you turn it "on" and then "off". The only way for it to not run is if you turn off the switch BEFORE you start the engine. When the engine is running and you turn the compressor on The PCM grounds the relay and you can even remove the ACM (programer) and CCP (climate control panel) and it keeps running. It sets no codes. I don't have a TECH I scanner but on a tech II PCM is displaying Compressor relay "ON" when you command it with the CCP but then will not allow it to turn off or display"OFF" the relay is grounded at the time data displayed is "ON" and not grounded when data reads "OFF ....Further more when the the CCP commands "ON" according to CCP data it comes "ON" but then while stay on til I kill engine and turn on key and turn off CCP then start the relay insnt grounded by PCM therefore compressor is off while engine is running.......just for grins I already plugged in a different ACM,PCM and CCP and restarted and get the same issue. Now I wouldnt worry so much about this except the car eats compressors . I have put three on now and the car only has 48,000 miles on it bought used at 12,000.Its like once you have a running engine and the pcm is told to ground the relay...it refuses to change that command. unplugglng the pressure switches will of course open the ground between the PCM and relay .......Can someone help me Please I will dance at your Wedding Link to comment Share on other sites More sharing options...
Cadillac Jim Posted January 23, 2013 Report Share Posted January 23, 2013 You should be getting this code: P124 (E124) A/C compressor circuit was shorted (ON) w/o request by HVAC If you aren't getting this code, then the PCM isn't trying to turn off the A/C. I believe that the PCM keeps the compressor going all of the time (except for cycling) to support the defroster, and to dehumidify the ventilator air. If that is correct, your observation that you have to turn off the A/C before starting the car may be normal. However, I believe that I remember from my owner's manual that you can turn off the A/C from the CCP (mine is a 1997 model year). I'll look in my 1997 FSM, page 8A-67-1. This is five years later than your car and there was a switch from OBD I to OBD II and lots of wiring changes, so others with a FSM or experience with OBD I cars may chime in to correct me. I see two possible problems here. First, the compressor may not be cycling, which would be a failure if the temperature sensor circuits on the A/C programmer or of the A/C high pressure switch. The high pressure switch is in series with the relay and cuts out for A/C compressor high side pressure over 430 psi. If it's not tripping, that could explain how and why your car eats compressors. The other is that there may be debris in your system from the first compressor failure that is ruining replacement compressors. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
snappytee Posted January 23, 2013 Author Report Share Posted January 23, 2013 thanks Jim I get a clean slate on the codes which is the amazing thing. Maybe the compressor is supposed to run all the time even when you punch it to "OFF". But I have never seen that before<LOL>....Hmm You DO have to request AC ON to get it on but the it won't cut off until you (STEP 1)kill the engine (STEP 2) Turn key on and punch AC "ON (STEP 3) Start engine PCM then pauses for about two seconds and then grounds compressor relay....and theres no getting it to turn off (except for normal cycling or wide open throttle disengagement) pressure switches are out of the picture because they would only open the circuit from the PCM to the relay...and the inlet and out temp sensor read about like the normal ambient temperature ,according to my TECH II...outside air temp (OAT) reads correctly too....I want to think it a serial data issue but the modules communicate data...however I am using a TECH II when the book says use a TECH I...if you find something Please contact me Thanks James . Link to comment Share on other sites More sharing options...
snappytee Posted January 23, 2013 Author Report Share Posted January 23, 2013 Oh I forgot to mention I flushed out system with 200 psi pressure using ac flush solvent many times ...its clean as I can get it. and I measured 8 oz fresh pag into it 1/4 oz gm dye. pressures look good high and low... used a kit that gives you all the parts and even pays me labor every time it fails.........they last about a year...and then come in with roasted looking clutch and noisy Link to comment Share on other sites More sharing options...
rockfangd Posted January 23, 2013 Report Share Posted January 23, 2013 I wish I could remember the 92 setup. I think it is similair to the newer ones. I have a 96 and 97. one has a auto/econ button. the econ turns the compressor off. The other one has an actual ac button that disables the compressor. Yours may be working normally. Are your cooling fans working properly? GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
Cadillac Jim Posted January 23, 2013 Report Share Posted January 23, 2013 I have a 1997 and it has an OFF button on the A/C console. The owner's manual tells you to use it if the alternator light comes on, as well as to push the headlight slider all the way to the left over the detent to turn off daytime running lights, lay off the cigar lighters, etc. But there are a lot of differences between the PCMs for the 1992 model year and the 1997 model year, and I don't have any information on the details of the 1992 model year at my fingertips. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
KHE Posted January 23, 2013 Report Share Posted January 23, 2013 If you press the OFF button or the ECON button on the climate control panel, does the compressor turn off? If not, there is a short to power somewhere in the compressor relay circuit. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
snappytee Posted January 23, 2013 Author Report Share Posted January 23, 2013 Hi Jim ahh....its an 1996 STS sorry about the confusion. If you want no full time compressor just make sure its OFF on the CCP /turn engine off and it will not come on after you restart engine... but if you hit the AC button it will engage and stay that way no matter WHAT you do ....it will not disengage (except for normal cycling) Link to comment Share on other sites More sharing options...
snappytee Posted January 23, 2013 Author Report Share Posted January 23, 2013 I took that 1992 off my Profile sorry about that Link to comment Share on other sites More sharing options...
KHE Posted January 23, 2013 Report Share Posted January 23, 2013 Hi Jim ahh....its an 1996 STS sorry about the confusion. If you want no full time compressor just make sure its OFF on the CCP /turn engine off and it will not come on after you restart engine... but if you hit the AC button it will engage and stay that way no matter WHAT you do ....it will not disengage (except for normal cycling) If the system is in AUTO mode, compressor operation (cycling) is normal. Pressing the AC button so that AC OFF is displaed will keep the compressor turned off. You mentioned the car eats compressors and that you had the system flushed. Did you replace the condenser? If not, trash from the failed compressor(s) will be trapped in the condenser and there is no way to flush a parallel flow condenser. What brand of compressors are you using? Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
snappytee Posted January 23, 2013 Author Report Share Posted January 23, 2013 flushed em and purged with 200 psi Link to comment Share on other sites More sharing options...
Cadillac Jim Posted January 23, 2013 Report Share Posted January 23, 2013 My A/C compressor went 120,000 miles, 60,000 of them in the L.A. area, before the reed valves started breaking up. I paid big bucks for a Goodwrench replacement but it paid off, as the clutch started slipping a couple of years later. This experience is, I believe, typical. If your car consistently eats a compressor a year, you have a problem with debris in your system. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
KHE Posted January 23, 2013 Report Share Posted January 23, 2013 flushed em and purged with 200 psi Did you replace the condenser? All the flushing in the world will not clean the debris out of a parallel flow condender. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
rockfangd Posted January 25, 2013 Report Share Posted January 25, 2013 Ok Glad you updated. A 96 STS same setup as my 97. stupid question I know but what happens when you hit the ac button. Does it show ac off on the climate display and the compressor still runs or does it not ever show ac off? GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
snappytee Posted January 25, 2013 Author Report Share Posted January 25, 2013 OK .....guess what ! I was checking it with the relay out plugged using a 12v + powered snapon test light . Turns out you cant do that because the ACM is looking for the certain resistance of the relay coil being in before it allows proper operation of the on /off mode......weird huh PS the reason I chked it that is because the the compressor was locked and I hadnt yet replaced it.....WOW I went down the wrong path that time Thanks so much for your help....perhaps I can help you some day ( I am a Cadillac Specialist in Houston) Link to comment Share on other sites More sharing options...
Cadillac Jim Posted January 25, 2013 Report Share Posted January 25, 2013 Great! Stay and help out. That's how I got started. I'm not a Cadillac Specialist, but I'm very good at electrical problems and have a lot of experience in DIY with cars forever, so I lean on my FSM to help out. There are technicians, including past and present Cadillac Specialists here, so you will be right at home. I suggest that you subscribe to this forum so you get an email whenever someone posts a topic. That way, if you see something you can help out with, you can chime in. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
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