Can someone help me point what color wire from the ecu that monitor
the alternator if charging or not charging. From ecu to the dash. I need
to know the wire color from the ecu.

I appreciate any help.

 

what?? it's called a voltage regulator

 

I don't know all the details (never had to mess with it) but I believe the S has a slightly complicated charge monitoring system, as it actually measures charge/discharge current via the "Electronic Load Distribution Unit" located in the under-hood fuse box. That's in addition to the 2 wires from the regulator (inside the alternator) to the ECM (wht/grn & wht/red in connector C). I don't think there is a single wire that gives a "go/no-go" signal.