Electrical problem, tracking suggestions

Son was driving our 70 Charger RT Sat. (we keep it at his house)
Gave me a call, said car died after a "POP", car would try to restart then die when key released.

I assumed ballast resistor and took a ride to where he was with a spare and my Fluke.
Well, resistor checked OK and new one didn't help.

Found a 15 A fuse blown, replaced it but same results. Had car flat bedded to his house, $90, not too bad.
I'm thinking ignition switch or shorted wire before the ballast??

So what would be the best way to test wiring tomorrow with my tester?
Charger has a Painless system we installed, been about seven years with no hiccups.

Thanks in advance, Joe

Shorted normally means a hot wire is shorted to ground on most automotive circuits which normally ends up with melted wires, evidently not so on your car.
It sounds like to me that you have a open, AKA broken connection, I would start at the ballast resistor normally run wire side and work back towards the ignition switch to find the open, maybe look first at the connection between the steering column harness and the harness under the dash feeding the firewall bullhead connector
Good luck, let us know what you find please, that will help others on here later

Thanks guys, what I expected to hear.
No bulkhead with Painless, so that narrows the problem.

Since the fuse was blown, I'm suspecting the switch or the wiring past the fuse.
Reasonable logic?

Thanks, Joe

I would start tracing the line of the fuse that blew.
I am pretty sure ignition wiring isn't fused like that. but could be wrong.
Sure it could be related, but I don't think it is the cause.

Found it! Open blue wire to ballast.
Wire got damaged apparently when we were using 12V supply from the blue for a trans temp. light.

All is good now.

Thanks to all for input...Joe

glad it was a relatively simple fix !