To connect camera and wireless transmitter to 12v I installed 4-way connector (any 2 pin connector will work, I just had spare 4 way trailer connectors) on the trailer AND on the towing vehicle, so I can quickly screw the camera to
license plate of TV when hitching the trailer and then move the camera back to Scamp's rear window to see behing the trailer when driving or backing.
For power I used backup
lights on the TV and taillights on the trailer.