Hello all ! First this is a great forum.
The commitment all of you have to this car is a kool thing !

My neighbor has an 87 supra / turbo and it is draining her battery.
The electronics have become wacky, Pass window won't work.
Lotsa dash/indicator lights, engine runs rough, driverside rear lights not working right.
LOTSA ELECTRONIC GREMLINS !!
Any advice on where to start
Also I looked at the little "diagnostic connector box on the driverside wheelwell and I can't figure which connector is what to try a self diagnostic.
Any advice much appreciated !!

i would start with just checking over all the wiring you can for any corrosion, any wires that the insulation might have come off possible touching another wire. look for anything damaged, and fix it first and then go from there. After that write back, and maybe we can narrow some stuff down once you make sure the wiring is kosher.

i agree with diamond, but when your ready to do the diagnostics try this site, it may help you decide which 2 terminals you need to wire up.

http://www.cygnusx1.net/supra/library/TSRM.../fi/FI_023.html

Good luck