I had posted this problem last year and thought I had it fixed. I have 1999 Supra Santera that I think has some sort of grounding problem. Temp gauge would spike making me think I was overheating added a secondary ground to that gauge directly to the battery kind of a band aid but problem solved. The next problem which I feel is part of the same problem is the fact that if I turn on two many accessories i.e. running lights, blower, bilge at the same time the boat dies. I mean dead no electrical power of any kind. It's like someone just yanked the battery out of the boat. After about 15-20 minutes every comes back boat fires up like nothing happened. I asked skidim.com and they said in the past they have seen grounding problems on Supras with the alternator. I remember the guy I bought the boat from saying he recently replaced the alt. So my question for you guys is can someone either say the way it's wired right or point me in a direction of some sort of wiring diagram. I have attached the best pics I could get. The only part number I could pull off of the alt. was 8RG2043 which is for the regulator I think which is Leece brand. The first pic shows the factory wiring harness with the black, orange and purple wires. The purple is not connected to anything (doesn't seem right?). It also shows the thick black wire that is mounted to the regulator and then goes around the front of the alt. and is then screwed in with a alt. mounting bolt.
The next pic shows where the factory orange wire is mounted to the alt/regulator
The last pics show the yellow, black, white, and green(this ones seems to be snipped off) coming out of the regulator and then being tied into the alt.
Boat runs perfect besides the dying thing which last year I just learned not to turn on to many things at the same time. Seems like the problem should be pretty easy to fix though. Any help or advice would be greatly appreciated.