Weird Brake Light Occurrences

ok, short back story incase your not following my
Build. Finishing my wire tuck, installed cobra booster, and tail lights are not installed incase that matters.

Got the electrical hooked up to do basic testing. Brake lights and hazards didn't work. Bad fuse (15amp) , changed it, hazards work, brake lights work for a few pumps then fuse pops. Tossed a 20a fuse in ( I know, bad idea) and did a test, they worked, then they flickered ( getting brighter not dimmer) and went to proper brightness ( was dim before but didn't realize )'and I see a small puff of smoke. I stopped, checked the harness and everything seems fine now... the rear light harness was just laying there..

My best guess is something was touching something

Sorry, should have explained that batter.

The smoke came from near the rear tail light harness. The harness was laying in the rear. So far it looks like part of the harness was contacting the frame somewhere.

Put the correct fuse in, did some more testing and can't make it happen again