I picked up the EcoHitch for the Model S and I need to get the harness wired in for the trailer lights. This is a light duty open motorcyle trailer that only needs rear lights and turn signals. What I can't get a good answer to is wiring the car up for the trailer: 1. For a basic flat four wiring setup do I actually need a power source other than pulling power off of the existing lines from the tail lights? 2. If I do need a power source, I plan to fuse it, but where do I tap to get power on the Model S? Typically I would tap off of the battery of the car at the posts. I am not looking forward to digging the 12V out and tapping that since it is already a troublesome part on the MS. My assumptions: - Standard wiring harnesses pull power from the rear tail lamps to power the trailer lights - Advanced wiring harnesses use a power block which is powered from a 12V power source to power the lights bypassing the use of the rear lamp power. Any help is appreciated Please correct me if I am wrong.