1949 Chevy with S10 swap. Beginner build with ambition!

[gigamanx]

Originally Posted by joedoh

I still think you are lacking a ground, and you have a ground loop that is letting the lights ground through the taillight bulbs

nothing and I mean NOTHING short of a dead short will pop a 25A fuse. an ATC type fuse will pass 300% its rated current for about a second before blowing. a dead short is the only thing that will pop a fuse instantly. that means you have something grounded that should not be (pinched wire, bare end touching metal), or you have something wired incorrectly.

that steering column thing catches everyone. once you understand that on a single bulb system the turn signal is actually the brake light, it just kind of clicks that you have to have the correct wiring at the column and brake switch.

1. battery to frame 2. frame to engine 3. frame to cab. Isn't that all of them?

I actually disconnected the tail lights and only have the park installed now. Same issue. I fashioned myself a test light out of an LED panel I had kicking around. I then turned on the park light switch. Touched the outside to the test light and then grounded it. Guess what, it lit. So the one thing I didn't think of is, what if the light fixture is shorting? That's the next check.