I suspect you still have a ground problem.

Is there an engine to body ground strap? It had one originally so needs a good one.

Also might need an additional ground strap from starter to ground point. I think I an one from the starter mount bolt to the chassis.

Any time I encounter a goofy electrical problem I suspect the ground.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.