AC Compressor wire question
Thread Starter
Pro
Joined: Dec 2006
Posts: 557
Likes: 4
From: Austin Texas
AC Compressor wire question
I guess the reason I love my C4 is there's always one more mystery ... like today.
I was cleaning under the hood of my '94 coupe for the TCA show in Boerne this weekend and was surprised to see one of the two wires from the AC connector to the AC compressor was cut or broken and, on investigating, found the rest of it apparently "stuck" under the aluminum hose connectors where it was "probably" or "possibly" caught on some past repair job.
Surprisingly the AC seems to run just fine but I would appreciate anyone who can confirm my suspicion so I can pull out the "stuck" wire (if that's in fact what happened) and reconnect the two ends. Or a picture from anyone of their wiring that might suggest the answer (the FSM isn't any help). An enlargeable thumbnail of my situation is below.
Many thanks!
John
I was cleaning under the hood of my '94 coupe for the TCA show in Boerne this weekend and was surprised to see one of the two wires from the AC connector to the AC compressor was cut or broken and, on investigating, found the rest of it apparently "stuck" under the aluminum hose connectors where it was "probably" or "possibly" caught on some past repair job.
Surprisingly the AC seems to run just fine but I would appreciate anyone who can confirm my suspicion so I can pull out the "stuck" wire (if that's in fact what happened) and reconnect the two ends. Or a picture from anyone of their wiring that might suggest the answer (the FSM isn't any help). An enlargeable thumbnail of my situation is below.
Many thanks!
John
Last edited by AustinJohn; Apr 14, 2009 at 08:12 PM.
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
On the front of the compressor is the AC clutch which should have a two pin connector plug. A two pin harness with a Dark Green wire and a Black wire plugs into that connector and the other end runs to the back/top of the compressor and plugs into another connector.
It appears someone has spliced into that harness to lengthen it and didn't wrap the wire harness with plastic conduit.
I don't see how the AC clutch can engage with that black wire cut unless the cut end from the black wire of the clutch is touching the compressor case and is completing the ground path.
The black wire is the ground path for the AC Clutch.
The Dark Green wire gets 12 volts from the AC Compressor Clutch Relay. When the PCM grounds the primary coil of the AC Compressor Clutch Relay 12 volts is then applied to the Clutch coil which will then engage the compressor.
It appears someone has spliced into that harness to lengthen it and didn't wrap the wire harness with plastic conduit.
I don't see how the AC clutch can engage with that black wire cut unless the cut end from the black wire of the clutch is touching the compressor case and is completing the ground path.
The black wire is the ground path for the AC Clutch.
The Dark Green wire gets 12 volts from the AC Compressor Clutch Relay. When the PCM grounds the primary coil of the AC Compressor Clutch Relay 12 volts is then applied to the Clutch coil which will then engage the compressor.
Last edited by Hooked on Vettes; Apr 15, 2009 at 12:16 AM.
Thread Starter
Pro
Joined: Dec 2006
Posts: 557
Likes: 4
From: Austin Texas
Many, many thanks for the response. You not only answered my question as to the correct wiring but the mystery of why it was working if the ground wasn't connected - the answer must be the "stuck" wire is actually grounded!
I also appreciate you reminding me about the component pix in the FSM. Several times I'm found them really useful and this is another example.
After all of this I'm inclined to believe this is one of those "If it ain't broke, don't fix it situations" but I will tape off the end of the cut ground wire.
Many thanks!
John
I also appreciate you reminding me about the component pix in the FSM. Several times I'm found them really useful and this is another example.
After all of this I'm inclined to believe this is one of those "If it ain't broke, don't fix it situations" but I will tape off the end of the cut ground wire.
Many thanks!
John
