[rsk289]

Jeff, as you may have seen on another thread I'm having the same issues (or at least I think I am). I have everything connected for my preliminary wiring check, but the motor is not running as haven't sorted exhaust or cooling yet.
I started out with the 'Lucas SF4' diagram, as published in period for MkIII/427. This shows the warning light connected to the stator connection on the VR. With this exact wiring setup and all good grounds, the red light never came on. By using first principles and Mustang diagrams, I have now done the following:
Batt positive connected to A (output) on alternator, with ammeter in series
Stator on alt connected to stator on VR
Field on alt connected to field on VR
I on VR connected to warning light, on to ignition-fed live

My red light now comes on, but I don't know if it's going to go off again when the motor runs. I am using a rebuilt '65 alternator (42A) and an electronic VR hidden under a black case.
Please let me know how you get on!
Roger