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a/c compressor don't turn on


clott

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I have a 95 deville. The compressor will not turn on. It was working fine. a few days ago it started to blow warm air out of vents after hitting a bump or going over a bump. When I turn the ac on to either auto or econ it blows out warm air but the compressor won't come on. I had everything replaced about 2 summers ago. Please help it's very hot here in Texas.

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Press and hold the OFF and HIGH buttons on your DIC and report the codes here, there are a few codes that will shut down your compressor, Mike

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Examine the condenser and all lines for oily residue - if the loss of cooling was that sudden, you should see it. If this does not produce any conclusive evidence, you will need to have someone leak test the system to determine the source of the leak.

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

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My hubby tried jumping the compressor on the low pressure side but it didn't work. if this info helps any. thanks. I'm going to try and see if I get any codes. I will post if I get some or not. thanks

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Simultaneously press and hold the OFF and WARMER buttons on the climate control panel and if there are any trouble codes, they will be displayed on the information center.

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

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Since there are no ACP codes, I would think the system has a full charge of refrigerant. When you push AUTO on the climate control panel, does the system stay in AUTO mode or does it default to ECON?

You said you checked the fuses - did you verift the maxi-fuse in the engine compartment? Some models have a fuse panel in the engine compartment as well as the interior of the car.

Another thing to check is to unplug the compressor clutch and check for 12 volts at the harness when the A/C is on. If there is 12V when the system is in AUTO, I would suspect the compressor clutch. If 12V is not present and the system has not defaulted to ECON, I would suspect some problem in the wiring to the compressor or a fuse.

Post back your findings.

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

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As Kevin said, on my 96 the COMP fuse controls the AC Compressor Clutch and Cooling Fans and there is a separate AC Compressor Relay. When you hit AUTO listen carefully to see if the relay clicks, I used a doctors stethescope and mine was not clicking (while engine is running its hard to hear it, see if you can feel it or use a listening device). You will need to remove the electrical housing on the LF wheel well to see the relays if you have not done so already. I had a bad low pressure switch that did not throw a code. Do you have a manual if not maybe someone can post the AC diagram from a 95, here is one from a 96, be careful its from a 96 and they make changes but it may help you..

As Kevin said, I checked for voltage at the compressor plug while the system was in AUTO and there was NO voltage..., because the relay was not energizing, because low pressure switch was not working correct.

If you have power at the compressor connector you probably have a compressor clutch problem as mentioned by Kevin.. If you don't have power the problem is elsewhere.

post-3-1119529366_thumb.jpg

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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We checked all of the fuses (under hood and in trunk), listened to relay switch with stethescope didn't hear anything.we also uplugged compressor/clutch plug no voltage. how do you check low pressure switch? or what else would it be? thanks for your help!!

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thanks for all of your help. we think that we have it figured out. there a is short in the wire harness on the clutch. i guess we will have to replace the wire.

NICE! I actually bought a new electrical connector for my compressor yesterday, it was $22... I was going to suggest that you call me, but it looks like you nailed the problem, Good Luck, Mike

Here is my AC Compressor thread, there is some good info toward the end of it.

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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where is your ac compressor thread?

SORRY! Ranger got it for you... Thanks Ranger

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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is the electrical connector also called a pigtail and/or coil? I called a online parts place and the rep told me that the part is called a coil. now I'm lost...please help..thanks guys.

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is the electrical connector also called a pigtail and/or coil? I called a online parts place and the rep told me that the part is called a coil. now I'm lost...please help..thanks guys.

NO they are wrong, and way off base, this connector connects to the COIL buried in the compressor to engage the clutch. From your description (a short in the wiring harness) you found a bad connection involving this plug.

Is it a bad connection and NOT the clutch coil component in the compressor?

post-3-1119556086_thumb.jpg

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Here is detail for the clutch coil....Notice #2 in the upper right hand photo, the hub has to be removed first. This is NOT a hard job to do, I just pulled the hub and clutch coil off my old compressor to see how hard it was to do, and it was easy... HOWEVER, I had it in a vice on my bench, I don't know how much harder it woud be to do on the car :blink: Mike

post-3-1119556595_thumb.jpg

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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so the part that i need is the electrical connector...right? thanks a bunch

The picture Scotty posted is sometimes called a pigtail. From your desctiption, you said the wiring was shorted. I think you mean opened or damaged as if it were shorted, the fuse would have blown.

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

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how hard/difficult is it to change out electrical connector? is the part that I need also called a/c clutch coil connector? I called my Cadillac dealer and that's how the parts dept referred to the part....costs about $23...can get at a local parts house in the morning for around $20. I probably will get it in the morning instead of going to dealer because the local store is a lot closer to me. one store said that they could order the part but it would be in sometime next week..to hot to wait that long....thanks

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The picture Scotty posted is sometimes called a pigtail. From your desctiption, you said the wiring was shorted. I think you mean opened or damaged as if it were shorted, the fuse would have blown.

thanks for the info..like you said not a short but I know something is wrong with it because when the hubby unplugged and tested it with his volt meter while car was running it didn't work then another time it did work and the a/c was working and blowing cold air.. We appreciate you guys. You have helped us tremendously. We did everything that we could today that you guys suggested. thanks again for all your help. I suppose now all we have to do is to replace the electrical connector.

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how hard/difficult is it to change out electrical connector?  is the part that I need also called a/c clutch coil connector? I called my Cadillac dealer and that's how the parts dept referred to the part....costs about $23...can get at a local parts house in the morning for around $20. I probably will get it in the morning instead of going to dealer because the local store is a lot closer to me. one store said that they could order the part but it would be in sometime next week..to hot to wait that long....thanks

It is EASY to change, I am about to do it. You will need to cut it back past the short if the short is in the wire. I plan to use heat shrink tubing and twist and solder the new JOINT... However there is a twist to this!..... The two condenser wires (GREEN and BLACK) have a DIODE connected between them in a snap connector. This undoubtely is there to protect the relay from the ON & OFF electrical feedback or transients that occur.. It MUST be put into its proper orientation, reversing the DIODE WILL cause problems and burn out the DIODE. I will post more info on this DIODE later, I had mind out yesterday and had to reinstall it... THAT is the only really tricky part....and it must be done correctly... I plan to install the DIODE on my bench and MARK which lead goes to GREEN.... STUPIDLY, the new pigtail connector comes with BOTH wires being WHITE :rolleyes:

Amazingly they provide CRIMP connectors in the new pigtail connector, I would NEVER use a crimp connector in this location. This connection MUST also be sealed from wet condtions. That is why I am using heat shrink tubing over the solder joint and them wrap it in tape...

Will post back later with some schematics, Mike PS: look about two inches up from the connector for a 1/2 long WHITE or BEIGE snap box, it looks like an in-line wire crimp connector... to see if you have the DIODE.. later!

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Ok see the picture below. In the lower right corner is the A/C Compressor Clutch DIODE. See the triangle facing a flat line? That DIODE symbol shows the proper orientation of the diode (that is the cathode end). See the picture I inserted in the upper right hand corner? That is what a typical DIODE looks like (mine looked like the black one). See the GREY LINE on the DIODE, that LINE and the LINE in the schematic that I discussed above (the cathodes) face the same direction (see tiny red circles that I made). In my case the LINE end (or cathode) of the DIODE faces the DARK GREEN wire and the other end (the anode) faces the BLACK wire..

You can AVOID all of this, if you carefully open that white/beige box and look at how the wires are oriented, watch how it comes apart (I didn't do that and needed to refer to the schematic). You can also avoid this if your short is closer to the plug and you can ignore getting involved with this DIODE altogether, it depends what you find..

PS: ignore the writing on the schematic, those are my notes while I was diagnosing my compressor problem.

Here is an interesting link on DIODES

http://www.kpsec.freeuk.com/components/diode.htm

post-3-1119576605_thumb.jpg

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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The picture Scotty posted is sometimes called a pigtail. From your desctiption, you said the wiring was shorted. I think you mean opened or damaged as if it were shorted, the fuse would have blown.

thanks for the info..like you said not a short but I know something is wrong with it because when the hubby unplugged and tested it with his volt meter while car was running it didn't work then another time it did work and the a/c was working and blowing cold air.. We appreciate you guys. You have helped us tremendously. We did everything that we could today that you guys suggested. thanks again for all your help. I suppose now all we have to do is to replace the electrical connector.

Did you locate the break in the wiring? It should be easy enough to solder it back together and apply heat shrink tubing.

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

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