I don't get any resistance at all. To make sure I had the meter set up properly, I measured from the body of the compressor to that ground screw and I was getting a little over 1Ω.

 

When you apply battery voltage to the clutch/coil you should have easily heard the clutch engage (that sound you hear under the hood, when the A/C kicks on). I think you've narrowed it down to either the clutch or coil or both. I had the clutch and coil replaced on my car. Maybe adjusting the clutch clearance would work, if it's out of spec.

 

I would think that you should get more like mΩ readings, because the metal should have pretty low resistance.

Try that resistance test between that ground bolt and a bolt on the valve cover.

Also, in the common diy thread on top of the gen tech help forum, there is a link to check hvac codes that you should try.

 

Another question, if I check for voltage on the socket side on the a/c compressor clutch plug with keys off the the ignition, I should not get any voltage, right?
With engine and A/C running I do get voltage.

 

I would ordinarily say you've proved the clutch coil is open, however first time you tried to drive the coil w/ battery voltage, you got sparks when you connected the jumper. This implies the clutch coil is intact and drawing current (3-4 amps).

To be sure recheck your coil resistance carefully. If coil is good, you should read less than 5 ohms. Not much different than a dead short so you have to have good connections to measure correct value.

If you again confirm infinite resistance (open) for coil, it's time to try to replace the coil. It should be possible to do in place w/o discharging and removing the compressor, but it won't be easy. Remove belt and alternator for access. Remove compressor from mount and reposition to remove clutch plate and clutch coil. Good C-clip plliers essential.

good luck

 

Well, it was in fact the coil that was bad. I bought a clutch and coil assembly and installed it myself. The old coil read resistance when I removed but it was really high. It looks like the ground bracket that attaches to the a/c compressor housing was pinching the ground wire and it was a little nicked.

The A/C does not cool low enough and that is due to the fact that when me and my friend checked the pressure he noticed that the low side was to high and he decided to lower the pressure by letting freon escape. Now I have to replace the schrader valves because one is leaking and that would required a vacuum leak and then service it. Hopefully everything works out.

I wanted to express my gratitude to you guys on this forum for the invaluable help.

Thanks much.