A few weeks ago I lost my V-belts, and when the AC compressor belt went out, it severed a wire that seems to be responsible for engaging the AC compressor clutch. It is barely visible, and located between the belt pulley and the body of the compressor. I would need to remove the clutch and pulley in order to access. It appears that the belt completely "de-gloved" the wire, leaving no wire insulation intact and just a mess of wire strands. My AC does not work at all at the moment, and attempts to work it will blow a 7.5A HVAC compressor fuse in the engine bay fuse box - as this wire is shorted against the body of the compressor without its insulation.

Has anyone had this problem before, and is it possible to fix this issue via a repair of the wire, and not a full-out replacement of the compressor?

Thanks in Advance.

Post a pic

Hi gristle101,
The wire powers the electromagnetic clutch under the compressor pulley. And yes, if it is broken, the compressor will not engage, and no AC cooling will happen. And yes, as you point out, if it shorts to ground, it will blow a fuse.
If you can twist the wire filaments back together and solder the wire, it can then be reinsulated with a little nail polish. This can probably be done without any disassembly. I always wondered how such a delicate wire could survive, but your posting is the only one I have ever encountered concerning a damaged wire over many years.
Andy

I've got the same damaged wire but mine was due to the rodents that love making 993's their home.

Andy,

Thanks for the information. I do think disassembly will be needed, as the wire did not cleanly break in the middle of itself... it pulled out of the clutch, entirely. There are no loose ends to re-marry together that I can touch without any disassembly.

I hope this doesn't kill my entire compressor... I am planning to loosen the compressor from its mount, remove the belt, and remove the bolt in the middle of the pulley/clutch assembly. Andy, or anyone else, do you happen to know if this is a straightforward removal/reinstallation? Anything I should know?

Yeah, when my V belts failed the steel braiding inside the HVAC belt wedged behind the pulley and cut this wire! Seems improbable. For archival purposes, I will post photos and results of my compressor surgery. I am dreading doing this as it's warm season and I will be dripping in sweat after about 5 minutes.

Hi Gristle,
The pulley/clutch assembly pulls off without opening the compressor.
Andy

Andy, this video you shared is basically exactly the procedure for disassembly of the compressor for our cars. I've done the fix and driven the car and everything is working now.

Again, for archive purposes, my HVAC belt (and alternator belt) failed and took out the wires for the AC compressor clutch electromagnet with it.

My fix could be done with the compressor still in the car so no messing with AC lines needed. Total time was 1 hour and this was very easy with the right tools.

There is an electromagnet which engages/disengages the clutch to regulate the AC compressor when the HVAC system commands it to turn on. The fuse for this electromagnet is a 15A fuse in the compartment on the left side of the engine. There is a feed wire which comes from the right side of the engine compartment, from the same area that the O2 sensor connections live. There is a little plastic door covering the spade connection of the electromagnet wire. This is the "hot" wire for the electromagnet. The ground is screwed to the body of the HVAC compressor as this is grounded with the chassis and engine case.

The electromagnet can be accessed by first loosening a 10mm hex bolt in the center of the HVAC clutch/pulley assembly. You want to do this with tension on the V belt so it will hold everything in place for you. Once you've got it broken loose, then you can loosen the (4) mounting bolts holding the AC compressor in place - I believe they are 13mm. Be careful not to drop the square nuts on the bottom of those bolts as when they fall into the engine it can be a NIGHTMARE fishing them out. Once these are loose, there is a final tightening bolt (believed 10mm) to the right of the AC compressor base, loosen this and the entire AC compressor should be free to slide to the left and take all of the tension off the belt until the belt can be removed. It is not required to fully remove any of these bolts holding the AC compressor in place.

Remove the 10mm hex nut in the center of the AC pulley/compressor. The clutch should pull right off now. Beneath it, there is the pulley and bearing assembly with a ring clip. Unlike in the video Andy shared, I have ring clip pliers - a kit is like $20 on Amazon, and as we are working on this in the car at a very awkward angle; this is pretty much a requirement to have. It saves a lot of time and swear words. Remove the first ring clip and remove the pulley/bearing. Mine required just 2-3 taps with a rubber mallet to be convinced to come off.

Beneath all that is the electromagnet. There is another ring clip that needs to be removed in similar fashion and this can pull off. There is a pair of wires on the right rear side of the electromagnet, and mine had almost nothing left of them. I used some speaker wire and soldered 4" to each of the (2) wires and covered everything with heat shrink insulation tubing (Amazon). The heat shrink can be activated with a heat gun, or hair dryer. The misbehaving V belts had also eaten away at a plastic subassembly that houses the wires, and there were some metal pieces exposed as it had basically been sanded down. I used 2 coats of clear nail polish to cover them as these are assumed to be energized electrical parts. Lastly, I used another larger piece of heat shrink tube to hold/combine the pair of wires together as these will be passing extremely close to the spinning pulley and V belt and we want a nice tight assembly.

The electromagnet can be reinstalled at this point, and more soldering and heat shrink can be performed on the ground wire and the hot wire feeding power to the electromagnet. In order to give myself plenty of slack wire to perform the solder, my lengths of wire were a few inches longer than before the problem, so I used a zip tie to hold them out of the way.

Finally, the rest of the installation is the reverse of removal.

The compressor, with a new belt installed, but missing its electromagnet wires.

Everything disassembled, I had removed the electromagnet and soldered new wire to it at this point. This photo shows the reinstalled electromagnet, before I soldered to the feed and ground wires.

Completed installation, after soldering and heat shrinking, I zip tied the slack to the bottom of the compressor mount hole/slot to keep it out of the way of rotating parts.