I had the brake light do that on one of my cars. What it ended up being had nothing to do with the wiring. The spring assembly on the front parking brake cable, under the car, had rusted and lost about 1” of length. At that point the spring could not keep the pedal high enough to stay off the switch. I reached down and manually pulled up the pedal assembly and the light went out. I then crawled under the car and found the “problem”. I replaced the spring with another original and the problem was solved. Duane
I suggested that in post #2, but never got a response about it. Not sure if Mark checked that or not.
My wagon's gen light is doing that for years. Haven't switched to LEDs in the dash. Checked the charging system. the Ol 36 amp alt was doing fine. Still on since I put in my one wire 150a power master Alt. Tim