Any experts on the Hardbody charging system?? alternator charge light wire??

[s13_240_rb20]

OK....I am seriously losing my mind.

My engine is the RB20DET, but I am trying to figure out the Hardbody wiring to make my alternator work.

There are two screw-on connections: I have 12v and I have the GROUND. Then there is the plug with a big white wire and a small white/red wire (charge light on dash?? dropping resistor???) They are different colors on the hardbody alt, iirc, so please just call them the big wire and the small charge light wire.

I have the big white wire run to the battery also. With the small white/red wire detached, it doesn't charge. Detached, the small white/red measures .006v. When I attach the white/red to the battery, I instantly see the volt meter jump to 16v or so (CHARGING!!! I think??). But then the engine stalls in a few seconds.

It does that every time!!!!!

I have been searching all day for the correct wire in the engine bay (from the truck's dashboard charge light system, which is a yellow/black wire behind the dash), and couldn't ever seem to make it work with the yellow/black wires I tried under the hood. every time it senses voltage given to the white/red wire, the engine stalls. Can anyone tell me what to do or if I can hotwire it some how and make it charge without stalling?? Or why it is stalling????

Thanks for ANY input!!

--TJ

[s13_240_rb20]

More specifically, does anyone know what kind of voltage the smaller wire on the plug is expecting?? I assume that a 12v reading on that line causes the alternator to start charging but at 17v, which is probably so high that the ecu shuts down the engine???

I'm soooo lost...

--TJ

[s13_240_rb20]

Nevermind. Luckily, I figured it out by trial and error without frying my alternator.

For future reference, there is a rectangular plug by the battery and it has 4 wires to it. Since mine was an engine swap, my wiring stopped at the female plug. I ran the small white/red wire from the alternator plug to the yellow/black wire on the female side plug. That yellow/black wire measured about 6 volts and when connected to the white/red alternator wire, my voltmeter connected at the battery jumped up to 15v at idle.

As I have previously found out, connected the white/red wire to 12v caused the voltmeter (at the battery) to jump to 17v and the engine would stall in a few seconds unless I disconnected that white/red wire from 12v.

Lesson: 12v on the white/red causes overcharge?? 6v on the white/red causes 15v charging (which is good I'm pretty sure).

--TJ