A/C Compressor Clutch Problem

[Mrlamo]

Ok,

I know I am new to this forum, but here goes.

I have a 1999 Escort LX sedan. The A/C was cuting in and out last year, but was in more than out and had good pressure readings so I didn't worry about it. This year the clutch won't start. So did some checking.

Compressor clutch does not turn.

Checked voltage at the compressor..13.5 while running.

Jumpered the Clutch from the battery...bam works. Clutch spinning and Cold Air.

Ok so how can the clutch work and there be voltage at the compressor and it not work.

Before you blame the connector I already jumpered right past the connector...nada.

Please help this is mind boggling!!

I would love to blame the CCRM or one of the pressure switches, but if they were bad I wouldn't be getting voltage at the compressor...I think?

I havn't checked the charge yet, but that goes back to the voltage if I didn't have a good charge I wouldn't have any voltage at the compressor...again I think?

Please advise,
Thanks

[ElectrolysisDoc]

Originally Posted by Mrlamo

... So did some checking.

Compressor clutch does not turn.

Checked voltage at the compressor..13.5 while running.

Jumpered the Clutch from the battery...bam works. Clutch spinning and Cold Air.

Ok so how can the clutch work and there be voltage at the compressor and it not work.

Before you blame the connector I already jumpered right past the connector...nada.

Please help this is mind boggling!!

I would love to blame the CCRM or one of the pressure switches, but if they were bad I wouldn't be getting voltage at the compressor...I think?

I havn't checked the charge yet, but that goes back to the voltage if I didn't have a good charge I wouldn't have any voltage at the compressor...again I think?

Please advise,
Thanks

2 things.
First, when you checked you voltage at the clutch, did you check your ground? Could this be a ground issue?
Second, you may have a wear issue on the surfaces of the clutch itself. Once this happens, the magnetic field made from the clutch coil is not strong enough to overcome the (worn) distance and spring pressure. Combine this with a little voltage drop, it might explain what is going on.

So maybe your jumper either supplied a missing ground, or increased the available voltage. Or both! Keep looking, your very close.

[Mrlamo]

Ok so when I was checking the voltage I was getting 13.5 whether I was using the connector for both wires or just the hot and then grounding to the body, so probably not the ground. I say probably because anyone who has dealt with auto wiring knows bad grounding can appear in the most mysterious symptoms.

Any idea how I check for worn clutch surfaces? Or the air gap? Thanks

[ElectrolysisDoc]

Originally Posted by Mrlamo

...Any idea how I check for worn clutch surfaces? Or the air gap? Thanks

With engine running, A/C on, (and wire plugged back in) Look for a magnetic field at the clutch pulley. Take a long screwdriver and reach down to the clutch. If you feel the magnetism, then try to "bump" the clutch plate to help it engage. If you have a field, and if if engages, your electrics are OK, it is a clutch wear problem. YIKES! Be super careful here, I'm asking you to stick a screwdriver near the belts of a running engine so think carefully about my suggestion, consider whether or not to proceed, plan your actions, and proceed at your own risk. That is the way I test. Some risk, but no guessing about the results.

[Ford Man 59]

Were you by passing the CCRM when the clutch kicked in? I know it's possible to make the compressor run with a bad CCRM if you by pass it. If I understand what you are saying in your post you're running current directly from the battery to the clutch, correct????

[Mrlamo]

Yes right from the battery to the clutch...I figured no messing around that way.