Alternator question, battery is discharging quickly.

[FC Zach]

Originally Posted by RETed

1) The 12VDC reference wire (which you call a "pin") needs to be connected to +12VDC constant, direct to the battery.
This is applicable to the FD and Kouki FC alternator circuits; prior to that, the Zenki FC alternators were only wired to switched +12VDC.
This tells the alternator what the status of your battery is.
Try not to connect it to the +12V post off the alternator, cause it'll be higher than the battery + post, and there's chance that you get back EMI from the alternator operation - this is why you don't see the OEM's wire it to there, even though it's a short shot.

Pin/Terminal. . . whatever, you know what was being referenced. But yeah, I am redoing the wiring now.

Originally Posted by RETed

2) The other pin is for the idiot light.
Like others who have already said, it's not necessary to connect this to anything.
This just completes a circuit (to ground?) so your idiots lights light up when the alternator fails.

That's what I thought too but is contradicting to what others have said. Some say it has to be connected and others say not necessary. .