Very clever idea
1. IF your Trailer battery is bad or dead or below 11 volts, you will NOT have Trailer Brakes at all
2. 4 Way flat gauge wiring cannot supply the needed power, especially if you attempt to tie into the Running light circuit. AND, I would worry about the Tow vehicles gauge wiring and fuse set up in its running circuit.
3. This system needs to be installed with a standard 7 way Bargman Trailer plug, that has the required Charge line run to the trailer. If no charge line to the trailer from the tow vehicle, the Brake system will slowly deplete the Trailer battery every time the brake system engages.
4. IF you have a 4 way flat on your truck(tow vehicle) AND your trailer, something is wrong unless the trailer is a utility trailer. RV camping trailers always have a 7 way Bargman plug on the trailer.
