01badbird

I put in a plug for a charger so I could use a lil wall charger to show off lights (rear BADBIRD lit panel,frt bird and the honeycomb DRL's and sidemarkers) for Autorama and was wondering what or best place to splice into so I could make a harness to plug into car when on trailer and the cars lights would mimic trailer lights for turns,brakes, etc . I was thinking just like wiring in a trailer harness but instead of on the output side maybe on input side wherever that might be? Is it legal?