I have been unplugging the alternator plug every night to keep the battery from draining. When I plug it in the next day the A/C clutch engages right away with a loud 'click'. I have run the wires but I can't find any abraided areas. I haven't replaced the alternator yet because I have the sick feeling it is something else.
I'm starting to think that there are just mutliple issues giving confusing and conflicting symtoms. It's possible the alternator has an issue that is feeding power back into the PCM and making it do weird things.
Anyone have any ideas???
Thanks,
Mark

 

So the AC clutch engages when you plug in the alternator plug with the key and engine off??

 

Yes, that's correct. It clicks on with the key off!!!!

 

It's really hard to figure this sort of problem out without a schematic, and the only thing that I have that is close is from my 85 Ramcharger manual, but the AC clutch circuit is your short. But I'm not saying the clutch it's self. Disconnect the AC clutch and see if your short goes away (with the alternator plugged in ). Use a test light to check for shorts by disconnecting the battery negative side and jumping the cable to the battery with the test light. If it lights up you have a short and if not your ok.

The AC clutch is doing it's job, it's just that you need to find out why theres voltage at the clutch with the key off. I would suspect the blower switch or something with the heater panel. Need a schematic.

 

Ditto....unplug the clutch it is located about 12-18 inches from the compressor. Then trouble shoot. Disconnect, unplug, or pull fuse, one item at a time till the problem is isolated. ...R C

 

Alternator plugged in, A/C clutch unplugged, still discharges. Alternator disconnected, A/C connected, no discharge.

 

Then plug it all in and start pulling fuses until your test light goes out. I really don't have any more input without seeing a schematic.

 

Have you tried unpluging the computer? It runs the a/c somewhat. Maybe there's something funny going on in there?

Just an idea.

 

No, haven't done that yet. I do suspect the computer, but it's only because I'm in the computer business!

 

Have you swapped the relays on the fender? Try swapping the A/C relay with the starter relay and see if the truck cranks on its own...

 

I did that, but every time the A/C turned on the starter kicked on!
Just kidding.
There are three relays on the fender, which is which? I can't tell from the FSM.

 

Front is ASD (alternator field supply, PCM controlled), middle is starter, rear is A/C (also PCM controlled).

 

Well, I swapped the ASD and the A/C relays and the compressor clutch clicked off, and the voltage stabilized. The real test would be to start the truck and run the air, then turn it off to see if the clutch stayed energized.
Oh, it will, I guarantee it!
Interestingly, I unplugged the ASD relay first and nothing happened....
The plot thickens.

 

I don't know what it means, but since switching the relays I haven't discharged the battery in two nights.
Might be coincidence....

 

Thanks again Dave (Wanna), looks like the problem was with the A/C relay or it's connector. Since I switched the A/C and alt. relays I haven't discharged the battery once.