clott Posted August 23, 2005 Report Share Posted August 23, 2005 HELP! The display on my 95 caddy deville says "low freon". My hubby and his friend checked the freon and it's not low. The compressor won't turn on. It just blows out hot air thru the vents. They tried disconnecting the battery to reset pcm and still the compressor won't turn on. his friend then hooked up a scannet to the car. then tried turning on ac with the scanner still attachd..then we got that p047 code (first time ever saw that code when checking codes on car) .I entered the diagnostics by pressing "off " and "warmer" and cleared pcm codes and still compressor won't turn on. When the pcm is cleared should/would it still show history? Please Help! It's very hot here in Texas. Thanks! these are the codes before clearing pcm... p047 history i022 " i039 " i052 " no acp codes " sir " t072 history t077 " and after all same except p047 was gone. Link to comment Share on other sites More sharing options...
KHE Posted August 23, 2005 Report Share Posted August 23, 2005 You stated that you checked the refrigerant level and it was not low. What method did you use? If the "Low Refrigerant" warning is on the DIC it usually sets a low refrigerant code which I believe is A047. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
Ranger Posted August 23, 2005 Report Share Posted August 23, 2005 Has the A/C ever been serviced? It is not uncommon for a 10 year old car to need a top off. Link to comment Share on other sites More sharing options...
clott Posted August 23, 2005 Author Report Share Posted August 23, 2005 yes , we had it completely redone about a year ago. my hubby said that he is getting power at the low pressure sensor but he isn;t getting any power to the compressor. any clue as to what it could be causing the problem? Link to comment Share on other sites More sharing options...
Ranger Posted August 24, 2005 Report Share Posted August 24, 2005 Assuming that what was done last year was done correctly and has not leaked, try pulling the plug off the low pressure sensor and jumper the connections on the plug. If that enables the compressor, then the low pressure sensor has gone bad. Link to comment Share on other sites More sharing options...
Scotty Posted August 24, 2005 Report Share Posted August 24, 2005 Here is a diagram of the AC system, the low pressure switch is #13, ignore the red circle it was for something else. My LP switch was bad and I was able to start the system by jumping the connector. I replaced the LP switch it was about $23 Link to comment Share on other sites More sharing options...
KHE Posted August 24, 2005 Report Share Posted August 24, 2005 Didn't you trace the problem to a broken wire in the A/C clutch circuit? If you've repaired that, then you need to determine if there is an adequate charge in the system. Your post earler stated that the system is not low - how was this determined??? This basic information is needed to help you diagnose you system. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
Scotty Posted August 24, 2005 Report Share Posted August 24, 2005 Didn't you trace the problem to a broken wire in the A/C clutch circuit? If you've repaired that, then you need to determine if there is an adequate charge in the system. Your post earler stated that the system is not low - how was this determined??? This basic information is needed to help you diagnose you system. Yes, Kevin, now I remember that, wasn't the problem a bad compressor connection? Wasn't this fixed? Link to comment Share on other sites More sharing options...
clott Posted August 24, 2005 Author Report Share Posted August 24, 2005 Assuming that what was done last year was done correctly and has not leaked, try pulling the plug off the low pressure sensor and jumper the connections on the plug. If that enables the compressor, then the low pressure sensor has gone bad. yes you guys helped me back in June and we bought the new connection that plugs into or on the compressor. we topped it off 2 weeks ago with freon. It was working and blowing cold air. now it only blows out hot air. he checked the voltage to the low pressure switch it's getting power. he also checked the voltage to the compressor and the compressor is not getting any power to it nor is the connection that hooks up to the compressor. Link to comment Share on other sites More sharing options...
KHE Posted August 24, 2005 Report Share Posted August 24, 2005 Assuming that what was done last year was done correctly and has not leaked, try pulling the plug off the low pressure sensor and jumper the connections on the plug. If that enables the compressor, then the low pressure sensor has gone bad. yes you guys helped me back in June and we bought the new connection that plugs into or on the compressor. we topped it off 2 weeks ago with freon. It was working and blowing cold air. now it only blows out hot air. he checked the voltage to the low pressure switch it's getting power. he also checked the voltage to the compressor and the compressor is not getting any power to it nor is the connection that hooks up to the compressor. It sounds like there is a substantial leak in the system. The ACM is doing exactly what it is supposed to do - disable the A/C in the event of a low refrigerant charge. This is to keep the compressor from being destroyed. Before you start jumpering sensors, you need to have the system leak detected and repair the source of the leak. Do not use any sealers or other snake oil in attempt for a quick fix - they don't work and many techs will not even touch a system after it has been contaminated with sealer. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
clott Posted September 5, 2005 Author Report Share Posted September 5, 2005 we and a friend are still trying to figure it out before we take it to a shop. can anyone send me a wiring diagram for the ac for my 95 caddy deville? Link to comment Share on other sites More sharing options...
Scotty Posted September 5, 2005 Report Share Posted September 5, 2005 I personally don't have a wiring diagram maybe someone else does. But, 1) what is the present state of charge? 2) will the compressor start if the low pressure switch is jumped? If the state of charge is low, DO NOT leave the pressure switch jumped.. If you disconnect the battery to remove the low pressure code, will the compressor run? Link to comment Share on other sites More sharing options...
PAUL T Posted September 8, 2005 Report Share Posted September 8, 2005 Assuming that what was done last year was done correctly and has not leaked, try pulling the plug off the low pressure sensor and jumper the connections on the plug. If that enables the compressor, then the low pressure sensor has gone bad. I have the same situation on my 92 Deville. I had it serviced about a year ago and this summer it has the "low Freon" code. I trust the shop that did the work did a good job. I have assumed that a leak sprung up since they serviced it. But from what you are saying, if I jump my low pressure switch, and the compressor comes on, then it is the switch and not a "low freon" problem? Will someone please clarify this. I have not hooked my gage up to check it for "low freon" yet. Link to comment Share on other sites More sharing options...
kcd1184 Posted September 8, 2005 Report Share Posted September 8, 2005 Just a little imput.. Both times this year that I had a problem with AC, the culprit turned out to be a bad stem in either the high or low pressure connect points. Once was with the Durango and I had it checked because it didn't seem to be cooling properly, the other was because of low level codes on the Eldo. When you hook up to see if your system will hold a vacuum , the only areas that are immune to scrutiny are the valves. Good places check with a dye . Under $250total for both. The valves are only about $2 but you have to have the other stuff and time and equipment . The knowledge is on this site. I still feel pretty good knowing where it could have gone. Kent Link to comment Share on other sites More sharing options...
KHE Posted September 8, 2005 Report Share Posted September 8, 2005 Assuming that what was done last year was done correctly and has not leaked, try pulling the plug off the low pressure sensor and jumper the connections on the plug. If that enables the compressor, then the low pressure sensor has gone bad. I have the same situation on my 92 Deville. I had it serviced about a year ago and this summer it has the "low Freon" code. I trust the shop that did the work did a good job. I have assumed that a leak sprung up since they serviced it. But from what you are saying, if I jump my low pressure switch, and the compressor comes on, then it is the switch and not a "low freon" problem? Will someone please clarify this. I have not hooked my gage up to check it for "low freon" yet. Do not jump the low pressure switch unless you have a gage manifold hooked up to monitor the high and low pressures. Most of the time, when the system displays the "Low Refrigerant" message, it is low on refrigerant. The risk of jumping the switch is that the system may be so low on refrigerant that the compressor could be damaged due to not enough refrigerant to circulate the oil in the system. I would suspect that your system has developed a leak since you had the A/C serviced. If the shop installed UV dye when they serviced the system, the leak should be readily identified with a UV light. How does the compressor clutch look? Is it oily/greasy? Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
Ranger Posted September 8, 2005 Report Share Posted September 8, 2005 I agree with KHE. Maybe I should have said "momentarily". I would not leave it jumped for very long. Link to comment Share on other sites More sharing options...
Scotty Posted September 8, 2005 Report Share Posted September 8, 2005 That is why I said this: If the state of charge is low, DO NOT leave the pressure switch jumped.. If you disconnect the battery to remove the low pressure code, will the compressor run? I had a bad low pressure switch, it set a CODE and the compressor was disabled. Jumping the connector turned on the compressor, which IMMEDIATELY told me that the switch was bad (I knew my system had freon it was just charged). I don't know why this has become so difficult to diagnose, we seem to be chasing our tails. If you disconnect the battery to clear the codes and the compressor starts, if you get a low pressure code it is 1) a TRUE low pressure condition or 2) a bad low pressure switch.... Link to comment Share on other sites More sharing options...
PAUL T Posted September 8, 2005 Report Share Posted September 8, 2005 If I understand this correct, you are just jumping the low pressure switch so the compressor will kick on long enough to measure the freon pressure. Then if finding out the freon is actually low then the system needs a leak fixed and recharged. But, if you find out the freon pressure is fine then the low pressure switch is bad. Is that a fair description? From the posts, I was getting the impression that ANYTIME you jumped the low pressure switch and it kicked the compressor on, the switch was bad. My compressor does come on when the battery is unhooked and it looks fine, but the code sets and compressor goes off. How long should the compessor be on in order to get an accurate pressure reading? Link to comment Share on other sites More sharing options...
Scotty Posted September 8, 2005 Report Share Posted September 8, 2005 Yes and No, I was immediately setting a low pressure code in my case, when I knew the pressure was NOT low, when I jumped the low pressure connector it confirmed that my low pressure switch was not functional. If you are able to erase the code and the compressor starts that kind of eliminates the IDEA that the low pressure switch is bad and you can do your guage testing. I will let Kevin opine on the length of time the compressor needs to run to determine charge condition, Mike Link to comment Share on other sites More sharing options...
PAUL T Posted September 8, 2005 Report Share Posted September 8, 2005 My compressor does come on when the battery is unhooked and it looks fine, but the code sets and compressor goes off. How long should the compessor be on in order to get an accurate pressure reading? I must clarify that my compressor only comes on when the battery is reconnected and the low freon code is cleared. Link to comment Share on other sites More sharing options...
KHE Posted September 8, 2005 Report Share Posted September 8, 2005 If I understand this correct, you are just jumping the low pressure switch so the compressor will kick on long enough to measure the freon pressure. Then if finding out the freon is actually low then the system needs a leak fixed and recharged. But, if you find out the freon pressure is fine then the low pressure switch is bad. Is that a fair description? From the posts, I was getting the impression that ANYTIME you jumped the low pressure switch and it kicked the compressor on, the switch was bad. My compressor does come on when the battery is unhooked and it looks fine, but the code sets and compressor goes off. How long should the compessor be on in order to get an accurate pressure reading? Paul, Let the compressor run long enough to record the lowest reading on the low pressure side and the highest reading on the high pressure side. Hold the throttle linkage to obtain a fast idle when obtaining the readings. The only positive method for determining if the system has the proper amount of refrigerant is to recover the charge, weigh it and compare the weight to the specification on the accumulator. Note that this is for R-12 as a '92 will have R-12 unless someone has converted it to R-134a. If it has been converted, a common mistake is to install a lesser amount of R-134a than what is called out for R-12 - the low refrigerant message will display every time in that case... I still think you have a leak in the system as it worked properly for a year or so and then displayed the low refrigerant message. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
PAUL T Posted September 8, 2005 Report Share Posted September 8, 2005 Thanks Kevin, I figured it is a leak also, but this talk of faulty low pressure switches got me wondering. Link to comment Share on other sites More sharing options...
KHE Posted September 9, 2005 Report Share Posted September 9, 2005 Paul, The pressure sensors are pretty reliable - Can you see any oily/greasy spots on any of the line connections or the compressor clutch? If the compressor clutch is oily/greasy, you probably have a shaft seal leak which wouldn't be out of the question given the car's age. Compressor shaft seals can be changed easily and inexpensively - if you can find a shop that doesn't just want to slap a new or rebuilt compressor on... If it is a shaft seal, be sure to replace it with the double lip shaft seal and it won't leak again. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
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