Subject: T&T: Re: Fwd: Ford Lehman wiring question The oil pressure switches and tach wires were disconnected on both my FL120s. (Don't ask!!!!)  For the life of me I can't figure out which wiregoes to external voltage regulators which have three terminals and whichconnect to the alternator.Help please.OliverSouthern LadyGrand Banks 42 Woodie Ford Lehmans, to my knowledge, never used external voltage regulators, so, standard wiring isn't going to apply for you. You should be able to get the external regulator wiring diagram from it's maker. (I.E. Balmar, etc.)  The standard Lehman wiring used an oil pressure switch to excite the alternator AFTER the engine started and had oil pressure. Presuming you have the original type Motorola alternator, and that you're looking at it from the back (wire) side,  one oil switch wire goes to the terminal at 3 o'clock. (that's the one that excites the field) The other oil switch wire goes to the terminal at 6 o'clock along with the ammeter wire. The tach take off is at 9 o'clock.  But since you have an external regulator, I'd guess you also have an aftermarket alternator?  Ken