i have just fitted a 21 circuit wiring loom to my truck
there is a wire labeled up alternator excitor so i connected it directly to the alt spade that i used to have a cable connected to
and the alt charges fine but the wire back feeds the fuse box as it stays live once the engine is running
this in turn keeps the engine running even once the ignition is turned off
if i pull the wire then the engine dies
so i put a 21w 12v lamp inline next to the alt and it works perfectly ?
can some one explain in idiot terms why this is so