Not Getting 12 Volts at Coil

Wow... I never even thought of the interlock. My '74 Cuda had one, it was disabled. Apparently disabling was common because a few books or groceries on the pass side seat would be enough to activate it. My apologies, I never even thought about it. It does sound like he had to do some digging to figure it out. It doesnt take too many hours to reach numbers like that. I do not believe the interlock could "spike" the module, but then again, I'm not very familiar with it or it's wiring. So that's more of an uneducated opinion rather than a definitive statement on my part... However, probing, grounding, or a surge in the positive battery circuit with the key on could pop a new one.