Re: New to me 2003 E450, looking for help!
Originally Posted by opus
The master switch generally removes the ground.
On 24-volt front-end loaders, and on highway coaches (with the switch in the battery box), maybe yes. On the ambulances, vans, motorhomes, and fire rigs I've seen, in cases where the switch was accessible from the driver's seat, it usually breaks the hot instead. On any given vehicle it could go either way, depending on the beliefs or opinions of the person designing the wiring.
I've made a decent living tracing these systems out using a digital meter, and scribbling diagrams on a legal pad.
Someone said "Making good decisions comes from experience, experience comes from bad decisions." I say there are three kinds of people: those who learn from their mistakes, those who learn from the mistakes of others, and those who never learn.