I just did a motor swap (96 4.3l from a blazer into my 83 Montero) and am having trouble with the Alternator draining the battery with the key off. the way I have it wired now is the positive battery cable has 2 leads to the Alternator (one to the back post, the other to the plug-"F/I" pin.) I then have a wire from the check engine light to pin "L". is this wiring correct, I have replaced the alternator to ensure the one did not have a short in it and I am still having this problem.

Thank you for any information.

Thank you,
Kyle

 

If you can get a pic or two of your set-up it might help. I think( and I might be wrong) your problem might be the second wire from the battery to the alternator(the one to the back post sounds right the other one I'm not too sure about). I've got a '96 S-10 with the 4.3 and I've only got one wire going from my battery to my alternator and its the charge wire with a fusible link in it.

 

I'll try and get a picture of it tonight when I get home from work, Thank you for your help!

 

This is the wire that I had plugged into the "f/i" pin in the alternator, I have since unplugged it and the whine that I had in the alternator is gone. I will see tomorrow if there is still a draw but I have a feeling that this was the issue. does any know what this plug goes to??

 

I've checked every wiring diagram I can find and the only wire that I can see that goes to the alternator is the charge wire. It's possible you may have fixed your problem with disconnecting that plug, but not being able to see where it goes I couldn't even guess as to what it goes to.