Alternator Wiring-2nd Question

[rich b]

That DA plug incorporates a diode in the wire which acts as a one way valve letting electricity from the ignition switch go to the alternator to excite it; but prevents electricity from the alternator going back to the ignition switch and onto to the coil enabling the engine to continue to run when the switch was turned off.

Same thing can be accomplished with an "idiot" light in place of the diode.