Alternator question

[rdkongs]

I may be the only person in the world crazy (stupid) enough to try to put a Mercedes turbo diesel in a 1954 ford pickup body. I am retired with too much time on my hands. The motor mounted up like it was made for the truck but I am having some problems with getting the wiring and vacuum systems working. The ford has a new EZ wiring harness that was connected to gas motor. It has a Alt power wire that goes to Bat and a Alt excitor wire that I assume will go the D+ terminal on the mercedes alt. Is that a good guess? I have heard that if the alt dash light is not functioning the alt will not charge. How does the light work into the system. Obviously I need all the help I can get. thanks

[sleepwalker]

quite simple.

when you turn "on" the ignition switch: battery positve>light>alternator - and light is "on".

this positive voltage will also excite the magnetic field on rotor to start charging. once it starts charging, that negative side will also become positive and it goes back to the light which got positive also from the other side... resulting in turning it "off".

[rdkongs]

Thanks for the info. Is the D+ terminal on the alternator the excitor?

[banshee350]

There are three termianls the two large ones are the charge to the battery the small one I think it is a 1/4 spade is the exciter also refered to in one diagram as alt proving. there is one termanal seperate from the otheres that one had a noise supresion module on it on one of my alt. Do you have any wiring or vacuum diagrams I can send you links to were you can get some.
P.S your not crazy you just have too much time on your hands
What motor are you using?

[C32AMG]

The alternators warning light bulb (voltage drop) is part of the excitation circuit, with out the bulb the alternator with not generate any voltage. D+ is the excitation wire goes.