MEMPHIS10CADILLAC

A/C COMPRESSOR WILL NOT COME ON!!!!

18 posts in this topic

i just had some work done last year on a/c compressor..i just tried to turn it on and it keeps switching back to econ,and compressor not coming on or making any noises..i changed relay,i checked fuses,i put a gauge on and it was in the red so we let some of the freon out to have it where it needs to show on gauge maybe thinking that too much was in it so the switch shut compressor down.that didnt work..so what else is there i need to check to see whats going on..tomorrow im going to get down under it and take the right front tire off and see if its anythang unplugged on compressor..not to long ago i had some dummies replace my transmission and im thinking the retards didnt hook everythang back up like it was.like i said it was working fine last summer til they start fiddling with my car.they already cost me a new radiator so any advice will help..thanks

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:welcomesmiley:

The first thing to do is to run the OBD codes and post them here. The link in my signature block goes to a Caddyinfo page that tells how.


CTS-V_Dashboard.jpg
-- 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.

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Check to see if you have power at the compressor. Then check if you have a good ground. Test the coil it should not be any more than 5 OHMS. If that is all good you should see what your sensors are reading if they are all in working order get a scan tool and see if you can activate your compressor from there. If you can you can safely assume that its not on the output side of your system. An insuffecient r134a charge can also make it not engage. Hopes any of this helps.

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Check for codes, it will turn itself off if the refrigerant is low to protect itself, that is the first place to start. Follow Jim's advice above


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Another possibility is a slipping A/C compressor clutch. If you can hear the clutch clicking but the A/C compressor doesn't spin, that is the problem.


CTS-V_Dashboard.jpg
-- 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.

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Another possibility is a slipping A/C compressor clutch. If you can hear the clutch clicking but the A/C compressor doesn't spin, that is the problem.

Jim you had it right the first time, he said its going to ECON, for me that happened when a low refrigerant or bad low pressure switch code was responsible.


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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:welcomesmiley:

The first thing to do is to run the OBD codes and post them here. The link in my signature block goes to a Caddyinfo page that tells how.

HEY JIM IT WORKED!!!!! THANKS....I WENT OUT AND READ OBD CODES AND I DONT KNOW WHICH 1 IT WAS I THINK RSS CODE.BUT AFTER I CLEARED SOME CODES IT STARTED CLICKING ON AND OFF..SEE YESTERDAY I PUT A GAUGE ON IT AND IT READ I HAD WAY TO MUCH FREON IN IT,BUT IT COULDNT BE BECAUSE I HAVENT TOUCHED A FREON BOTTLE SINCE THEY WORKED ON THE COMPRESSOR AND GOT IT WORKING PROPERLY..SO I PUT SOME FREON IN TODAY AND SO FAR SO GOOD IM BLOWING SNOWBALLS...THANKS FOR THE ADVICE,U ARE A REAL CADILLAC DRIVER LOL.

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2 days ago you said the gauge was in the red, overfilled? now you say it was really too low? you got it working so i guess your happy. you could have system evac'd and properly filled so you know the right amount is in car but that costs money.

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2 days ago you said the gauge was in the red, overfilled? now you say it was really too low? you got it working so i guess your happy. you could have system evac'd and properly filled so you know the right amount is in car but that costs money.

KHE is our resident expert. BUT I'll try to relay what I learned from him.

those gauges are tricky things & are difficult to get a true reading. seems you might have been a little low on refrigerent (& to make things worse, you let a little more out). what I did when I needed to add, was to clear the code - which lets the compressor at least turn on so it can suck the refrigerent in from the filling can. no need to bypass the sensor. Once the coolant starts getting sucked in, by the time the sensor would have detected it's low, it has already been getting charged.

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The gauges aren't accurate in terms of what readings should be unless the A/C is turned on and functioning, and the compressor is running, and possibly other things like temperatures of the A/C refrigerant lines.


CTS-V_Dashboard.jpg
-- 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.

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Ahh its possible that you erased the low pressure code, if there is a low pressure code present the compressor will not start, it must be deleted/erased


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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i assume he used a bottle of freon with the built in gauge. high tech stuff. its a 96 which is r-134a and uses threaded connections. pretty easy to hook up fill hose. just screw it on. system is pretty low if compressor won't turn on but guy added proper amount to blow ice cubes. so system is properly charged.

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Those cheapo gauges you can buy by the freon are junk. For my DTS it claimed it was in the red when in reality it was where it needed to be. Dont go by those junk gauges people, use a real set of gauges.

From the ALL CAPS post I thought it was the end of the world! Just the beginning of the summer season and a few new members needing help with their precious a/c :) Hopefully a few stick around :)

Edited by CoupeDTS

* 1966 Deville Convertible

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* 1996 Fleetwood Brougham Black on Black V4P -Gone
* 1983 Coupe Deville Street/Show Lowrider -Gone

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* 2000 Deville DTS - Silver with Black Leather and SE grille GONE
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Those low side only gages are worse than worthless. By not monitoring the high side, the system can be severely overcharged - I worked on a Chevy van a few years back that the owner kept adding R-134a to the system because it didn't cool. The high side pressure was close to 400 psi yet the owner stated the needle was still in the green zone on his tire pressure gage. I recovered the refrigerant, and charged it with the proper amount and it cooled fine.... I also drained about 10 ozs of oil from the system....

If you hook the low side only gage up whan the engine is off, they will read the static pressure in the system and the needle will be in the "red zone". The readings need to be taken with the compressor running and right before it cycles off.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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:welcomesmiley:

The first thing to do is to run the OBD codes and post them here. The link in my signature block goes to a Caddyinfo page that tells how.

yes i have ran the codes cleared the codes the only code relevant seems to be a cooling fan circuit problem ...sooooo i disconnected both fans and still blows the 10 amp fuse ? i assume if there is one of the 3 fan relays bad maybe THAT is blowing the fuse ,i dont think a clutch problem or high pressure (too much gas) would cause the fuse to blow .is there a relatively simple way to check the relays one by one with a multimeter? or do you have another idea?

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I have an 05 deville.the serpentine belt split down the middle and ac stopped working...i believe the belt broke the wires on the clutch to compressor..every thing from freon to power to compressor is fine..no codes came up..could it be something else?? The garage said it most likely the top wire to compresser and i need to replace the whole unit..i felt no wires broken in between the clutch.just dont want to replace it and find out thats not the issue

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First, I can't believe that you have no codes if the A/C clutch doesn't engage with the A/C on.  If the PCM is preventing the A/C from engaging the compressor clutch, there will be a code that tells you why, such as refrigerant pressure or temperature problems.  I'm not sure, but if the PCM thinks the compressor is running but the coolant pressure and temperature don't reflect that, you should get a code; someone more experienced in A/C service for your model will know for sure.

Make sure that you are using a good code reader that provides Bnnn codes.  I believe that OnStar will give you A/C codes but I'm not sure; you could call them and ask if they give you A/C codes.  If you aren't sure, go to Autozone or another outfit that reads all your codes for free.

Second, if you have a voltmeter or test light, you should be able to work a probe into the contact at the compressor DK GRN wire.  If it reads volts when the compressor clutch is supposed to be engaged, the wire is OK.  If the clutch doesn't engage when there is battery voltage on the DK GRN wire and the BLK/WH wire is grounded, the clutch is bad, or the safety A/C Pressure Temperature Switch inside the clutch is bad.  AC/Delco replaces the clutch and compressor as a unit.  But, watch for the belt slipping on the pulley as the cause of the compressor not turning.

Third, the A/C compressor relay is a $4 throwaway part, like the fuel pump relay.  Rock Auto sells that relay, AC/Delco, for $7.31  There is also a 15 Amp fuse in the underhood fuse block marked AC CLU.  The relay is right there on the underhood fuse block and it is also marked AC CLU; there may be a legend on the inside of the cover over the fuse block that tells you which fuse/relay is AC CLU.  While you are at it, check the ground BLK/WH wire coming from the compressor clutch for a good connection to ground (use your ohmmeter or a test light).


CTS-V_Dashboard.jpg
-- 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.

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One last thing - check the routing of the serpentine belt to make sure that it isn't re-routed somehow.


CTS-V_Dashboard.jpg
-- 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.

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