Working in a custom brake light

[BlindRonin]

So I'm wiring in a custom led brake light for my under tail. Using a led trailer brake light and im having trouble.

I've wired it per diagram but can't get the damn thing to light At all both lights are 3 wire I will

Pic of factory wires correct me if I'm wrong white with black is brake light switch, black/white is running light, and brown is ground? The trailer has 3 as well red, black, and white red is stop light black is running and white is ground.

This thing is kicking my ass.

[92xjunker]

Ground the - for the new light. Probe the other wires from the bike to it. LEDs are polarity sensitive. +to- -to+ = no light. Also make sure you didn't blow a fuse.

[BlindRonin]

Alright got it worked out thanks Junker.