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New Compressor Installed-Clutch not turning on-whats wrong?

Old Aug 12, 2006 | 03:34 PM
  #11  
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Originally Posted by IKZ
Just to be perfectly clear here...I should take off the compressor, and apply 12 volts DC from the battery to the two terminals just above the clutch (where the connector attaches to the compressor). If the clutch turns, then there is a problem somewhere else, if it doesn't turn, then the compressor is bad. Correct?
You don't have to take the compressor off the car to do this, but if you want to test it on a work bench, then that'* cool too.

Yes, If you apply 12 VDC to one of the compressor clutch contacts (the connector that pokes out from behind the pulley), and ground to the other, you should hear a click and the center of the compressor will spin along with the pulley. It'* not a lot of current in there, the fuse that runs it is only a 10amp one. The clutch itself is magnetic, when it engages the magnetic field created by the coil locks the pulley and hub together. If the clutch works, then you have a wiring problem.

You can also connect a regular 12volt light bulb to the compressor clutch connector in place of the clutch and see if 12 VDC is getting to the clutch. (bulb should light when you jumper the contacts at the relay or the low pressure switch. If the bulb lights up, juice is getting to the clutch and the clutch is dead.

BTW, you did transfer the pressure switch from the old compressor to the new one right? (It'* the one that plugs into the back of the compressor and is held in by a big C-Clip)
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Old Aug 12, 2006 | 04:02 PM
  #12  
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No, i didn't transfer the old....I got a new one

I pulled the compressor and applied 12 volts to one lead and ground to the other. The clutch did pull itself into the compressor. So that rules that out.

Should I be able to turn the clutch by hand at all? I cant, just wondering if I was supposed to be able to?

So has this boiled down to a wiring problem? Doesn't seem quite logical to me (not denying the facts here) but my old compressor had to be replaced because the clutch pretty much broke loose from the compressor. Everything worked fine i.e. the clutch engaged the compressor. It was making a horrible squelling sound (because the clutch was like free wheeling around the shaft in the middle of the compressor). So i got a short belt for a time until I had money to get a new compressor. So im not quite sure how it would boil down to a wiring issue when the wiring was working fine before i took the old compressor out.

Kinda odd in my opinion, but that is the nature of the beast i suppose anything is possible. What else could i do to eliminate parts, or connectors, etc. It seems like finding out what is not wrong is the way to track down the problem...gotta love process of elimination.

I really appreciate your help here..Thank you!

What route should i take from here?
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Old Aug 12, 2006 | 04:12 PM
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Originally Posted by IKZ
I pulled the compressor and applied 12 volts to one lead and ground to the other. The clutch did pull itself into the compressor. So that rules that out.
Yep, Clutch is OK then, it'* got to be in the wiring. Try the lightbulb test I was talking about starting at the clutch connector and working your way back into the wiring.

Just a side note, the clutch on my 1990 Bonnie failed in the same manner. And in the process of doing so, shorted out the clutch connector (melted it actually) and wrecked some wiring too. You may be in a similar situation.

The compressor is usually very hard to turn on a new compressor. If you had to add the pag oil youself before installing it then you need to turn the compressor by hand a few times to circulate some of the oil through the compressor and lubricate it. You may need a strap wrench to turn it. (I used a flywheel holder for my Honda motorcycle to do it) Anything that will give you some leverage to turn the compressor. Don't mess with the nut in the center of the clutch.
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Old Aug 12, 2006 | 04:19 PM
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ok...im off to find my test lamp and test the connector. Where does the wiring from the connector lead to. Am i ok pulling off the plastic loom to find out?
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Old Aug 12, 2006 | 04:23 PM
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This is turning into an electrical issue. Moving to the Electrical forum!
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Old Aug 12, 2006 | 04:36 PM
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ok...

I have a test lamp (it has one wire that comes off the back and has an aligator clip on it.) I'm not positive how i am supposed to test the connector. But i tried anyway.

I clipped the aligator clip onto the ground battery terminal. I started the car and turned the ac on, then i stuck the probe of the lamp into one of the connectors openings (the green wires side). nothing lit up. Then i jumpered the connector that plugs into the accumulator and i got nothing. Then i moved the probe to the other port of the clutch connector and tried to jump the low side connector again....still nothing.

Then i moved the aligator clip to the positive terminal with the probe in the side with the green wire. Tried jumping and nothing happend. But when i moved the probe to the other side of the clutch connector, the lamp lit up. Jumping the connector at the accumulator didn't do anything anytime. The only time the lamp lit up was when i put the aligator clip on the positive bat. terminal and the probe into the connector (the side with the dark colored wire...could be black or brown.) When i moved the probe to the other slot, i got nothing.

The compressor is still off the car. I ran the short belt for the test. Did i do everything right?
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Old Aug 12, 2006 | 05:48 PM
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Good, Black wire must be the ground connection ( Positive battery, through test lamp, to black wire = light always on.)

Now focus on the green wire, it'* the hot lead from the relay and will only have +12VDC on it when the clutch is supposed to be on.

Leave your tester connected to the negative post of the battery and start poking around in the relay socket. (Refer to the wiring diagram stamped into the body of the relay) There are only four connections on the relay. Two are the coil that closes the contacts. One (Probably Orange or Pink) is the power supply for the clutch circuit. And the last contact will follow all the way back to the clutch and it'* the green wire.
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Old Aug 12, 2006 | 06:00 PM
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Yup there are four wires going into the relay. A green, a light green, and two pinks. All of them come off of the relay and go into the firewall behind the accumulator.

What should i be doing at this point? Should i reinstall the compressor yet?
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Old Aug 12, 2006 | 06:14 PM
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Originally Posted by IKZ
Yup there are four wires going into the relay. A green, a light green, and two pinks. All of them come off of the relay and go into the firewall behind the accumulator.

What should i be doing at this point? Should i reinstall the compressor yet?
By all means. Daylight'* burning and it isn't the cause of your problem. Might as well get the A/C system sealed back up and a belt on it while you figure the wiring out.

As to the relay wires, the green one needs to be traced down to the compressor clutch. If you have a volt meter, then check continuity of that circuit. The pinks are +12VDC with the ignition on (typical GM color coding of wires) and you should get lights on them anytime the ignition switch is in the run position, One of the pinks is supplying the power to the relay coil, the other is power for the AC clutch when the relay closes.

They may go into the firewall, but they gotta come back out to go to the engine harness wiring and down to the clutch. I'm digging around for a wiring diagram, but may have to bow to someone with the same model year as yours to help you figure out how it'* routed.
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Old Aug 12, 2006 | 08:14 PM
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Originally Posted by IKZ
BTW, i will take it to get a vacuum put on it. Thanks.

What is the proper name for this...Evacuating?
Yes, whenever you break integrity on an air conditioning system (refigeration system) , you should evacuate the system. This removes all contaminants & non condensable gases & serves as a "drop test" to see how well the system holds vacum. This is basically a leak check for joint strenght & tightness. You also want to limit the time you have the system/accumulator open to atmosphere as this will degrade the accumulator. Additionally, on the newer Bonnes there is a clamping diode across the 12v supply to the clutch solenoid. Also on the newer cars (2000+) the low pressure interlock inputs to the PCM, the PCM in turn closes in power (switches ground in for the coil of the A/C clutch relay) for the A/C clutch. Not sure if this applies to the older generation Bonneville A/C plants, but might be worth while checking into, or maybe it'* a mute point.
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