04-05-2020, 10:16 AM
If you have only two wires from the new taillight, a red and a black, the red goes to the green/yellow for the brake. The taillight black goes to the brown/black for running light/taillight. The body of the taillight grounds through the metal fender.
When you hooked the red to the green/yellow, and the black to the green, and hit the brake pedal, both filaments were lit, the brake light brighter so you didn't notice the taillight filament.
The power was coming in through the green/yellow, through the brake light filament to the bulb's shared metal casing, into the taillight filament, through the black wire and into the green ground wire.
When you hooked the red to the green/yellow, and the black to the green, and hit the brake pedal, both filaments were lit, the brake light brighter so you didn't notice the taillight filament.
The power was coming in through the green/yellow, through the brake light filament to the bulb's shared metal casing, into the taillight filament, through the black wire and into the green ground wire.