Hi,

Going though the testing of my A/C system. Attempted to test the compressor by disconnecting the single wire clip and sending 12 volts off the battery to the compressor. I got nothing. Just want to confirm I tested properly before confirming the compressor is toast.

Picture below- I sent 12 volts directly to the white clip you see hanging on the A/C line.

it is an 86 22re/5 speed

 

Ok, well that's not testing the compressor. That's testing to make sure the magnetic clutch is engaging to TURN the compressor. Which you can replace just that.

 

Thank you for the reply. So based on this test it seems the clutch needs replacing at the least.

I am also not getting the A/C button to light up when depressed and have checked the fuse as well as hear the relay click. The system is empty of R12 and I suppose that could be why the I get no green light.

 

You should hear the clutch energize when you put + voltage on the lead. You can also test the resistance of the stator coil. You should get 3.4-3.8 ohms (at 68 degrees F) between the lead and ground.

 

The system uses hi/lo pressure sensor to keep the compressor from turning on if there is not enough gas or too much. With the engine running, if you put 12v to the compressor clutch, it should kick on and turn compressor.

 

with no refrigerant in the system the cluch will not engage. the light should come on anyways , but maybe it does 't . jumper the low pressure control to see if the cluch is good.

 

Ok so I ended up ordering a reman compressor. My Plan is put it on, replace dryer and expansion valve. Replace all o-rings and swap in R-134a compatible oil and charge. Anyone see an issue with this plan? If it does engage at this point I would have to assume I am down to fuse/relay or switch under the dash.

 

I've always taken my AC work to a shop. When the mechanic tested my compressor he had it out of the truck and showed me it was froze up.
The shaft would not turn.