A/C compressor clutch stopped engaging

[crazyd]

Hi all, quick synopsis here:

• A/C Compressor stopped working suddenly about a week ago.  Been working on other things (PS pump) but I don't think it was anything I did.
• Clutch is not engaging.
• Checked pressures, have 65psi on low side and holding.
• Checked connector at compressor.  Reseated.
• Ran power test in the manual, removed compressor relay and tested brown wires (CKT 250) to ground. 0.02v instead of battery voltage with ignition on and MAX A/C.
• Manual says open CKT 250 or blown A/C fuse.

I checked the brown wires underneath the RSEC and they proceed into the harness like normal, but I don't know where they go from there.  I really don't want to tear apart the harness trying to trace it or figure out if there's a remote possibility the wire suddenly broke somewhere down the line.  That will have a high probability of breaking something else.

There is no fuse labeled A/C in the RSEC, but I tested all the others (including the big 30/60 amp ones) and they're all good.

Suggestions?  I was thinking I could just splice the input brown wire back into +12V from somewhere else in the RSEC.  Since it's still fused through the RSEC this shouldn't cause a problem.  Thoughts?

Edited September 15, 2018 by crazyd

[ManicMechanic]

Jump the connector at the pressure switch in the A/C line and see if the compressor engages. If so, it's the switch which are known to go bad.

[crazyd]

I don't think that's got anything to do with it.  Looking at the schematic below, the pressure switch is part of a separate circuit (on the left side) from the 250 (right side) where my problem is.  It would make sense if the pressure switch interrupted power to the 250 but it doesn't appear to be that way.

[Imp558]

If there's power at the fuse and not at the relay you'll probably find a rotted connection at splice S120, most of those splices were crappy steel crimps wrapped in something resembling black duct tape.

There's an outside chance it's a crappy steel crimp in a piece of heat shrink filled with wax. And I suppose rodent damage isn't off the table if you don't know where the car was before you.

The bottom line is there should be power on that circuit with the ignition switch in the run position. 

[55trucker]

Dave:

 

if using a jumper wire directly from the battery to pin *5* (87 in the relay) at the compressor relay in the RSEC can you get the clutch to engage?

Edited September 15, 2018 by 55trucker

[crazyd]

Steve:  I'll try that over the weekend and see what happens.

Imp558: Where would I find splice S120?

I've had the car nearly 15 years, I think it's safe to say that anything that's wrong with it at this point is on me - but it has never had rodent issues, thankfully.  It was a factor at my last house but not at the current house.  Birds, and salty air from the beach are the only problems here.  But a tinkering owner is its greatest threat right now, and I've been doing a LOT over on that side the past couple weeks trying to find the source of a noise that eventually turned out to be the power steering pump.

[Imp558]

Assuming the relay and fuse are inthe same electrical center the splice should be laid into the harness leading into the electrical center or underneath the electrical center.

[crazyd]

Fixed!   The clutch was engaging jumping power to pin 5.  It was a blown fuse and a bad relay.

[55trucker]

Cool,

 

*at least ...you should be now*