[camcojb]

sounds like a grounding issue or loose connection to me. Have you ever tested the battery voltage at the battery when this condition occurs? I'm going to guess that the battery voltage is probably not real low, but a poor/missing ground or loose positive or negative connection is what's happening.

I would also rig up a manual bypass for the neutral safety switch just in case to test when it happens again; if the switch is faulty or misadjusted it will not turn over at all. Do the lights work when this happens or is everything dead?

Jody