A/C Compressor Clutch Resistance


jnuckols
12-13-2010, 10:27 PM
I have a 1995 Civic DX and the compressor clutch will not engage. I followed the circuit all the way to the thermal protector on the compressor and unplugged the wire from the thermal protector to the clutch coil. If I jumper 12 volts directly to the clutch coil it still will not engage. I do get a spark, though, when I touch my jumper to the connector. Does anyone know what the resistance of the compressor clutch coil should be, or any ideas why the clutch won't engage even with 12 volts straight to it?

Thanks.

amy@af
02-07-2011, 11:16 AM
try to turn by hand, the clutch on the compresor. If doesn't move it's seized.

The clutch is on the end of the pulley. It should move but not spin. Start the car & visually inspect

jnuckols
03-16-2011, 09:26 AM
Thanks. Compressor not seized. Just the clutch would not engage. I replaced the clutch only and solved the problem. Well, now there's another problem -- after an hour or so on the highway, the A/C stops cooling. A check shows that the refrigerant level is low, but there are no detectable leaks. It's seems like the system might be dumping refrigerant suddenly. Maybe an overpressure?

try to turn by hand, the clutch on the compresor. If doesn't move it's seized.

The clutch is on the end of the pulley. It should move but not spin. Start the car & visually inspect

BullShifter
03-17-2011, 08:41 PM
Was it it filled with the correct amount? The only way to to is to evac & recharge using the correct weight. The best way to find a leak is with dye added to the system. Then a black light is used to trace.

jnuckols
03-29-2011, 01:42 PM
No, did not evacuate. System still had some refrigerant in it, and I added more. When I was doing this for a living many years ago, we didn't fill by weight. We filled by pressure specs. I had about 30 psi on the low and 225 on the high. Does that sound like reasonable pressures?

BullShifter
03-29-2011, 09:51 PM
The pressures sound ok but that system hold such a small amount. If it were me I would evac/recharge. Every A/C machine I have ever used went off weight. All cars have a sticker stating the capacity in weight not pressure because the pressures change with air temps. It's only way to know you are exact. Couple ounces over could easily over-charge.

jnuckols
05-30-2011, 12:24 PM
Sorry for the delay. The car goes off to college, and I only get to work on it when it comes back home. The main problem turned out to be the A/C controls in the dashboard. The compressor was turning off. Got another control from junkyard and it works now. I'll take your advice about evacuating and properly charging. I think the A/C should be colder, and that might just be because there's too much refrigerant. Thanks. Oh, and I was mistaken about the system being low on refrigerant -- someone else had checked for leaks and I misunderstood him to say that it was low.

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