How to Mount a License Plate on a Trailerby Nicole Schmoll
States require trailers to have license plates with lights mounted to them to properly identify them. Lamps help protect drivers and trailers from collisions on the road, by flaring when the driver steps on the vehicle's brakes, to which the trailer is connected. Mounting a license plate onto a trailer is a simple process that anyone can perform with a license plate mounting bracket.
Purchase a license plate mounting bracket and lamp kit from your local auto parts dealer. Attach the license plate mounting bracket to your license plate using two bolts and nuts. Set the mounting bracket against the back of your trailer license plate and thread two bolts through the holes. Tighten with two nuts so that when looking at the front of the license plate, the mounting bracket steps down and forward.
Remove the mounting bolts from your trailer plate lamp and set them aside. Thread the remaining screws through the two holes on the top of the license plate mounting bracket so that the light shines down upon the plate, in accordance with state law.
Locate two holes on the rear wheel of your trailer and insert the two screws protruding from the back of the lamp (which is now connected to the license plate via the mounting bracket) into the wheel base surrounding the left or right trailer wheel.
Hold the light flush against the wheel base with one hand and thread two lock washers followed by two retaining nuts onto the back of the lamp, on the underside of the wheel base. Tighten the retaining nuts with your fingers first and then use a size 10 mm socket wrench to secure them to the wheel base, which may require about six to eight turns of the socket wrench.
Grab the lamp's three wires which are hanging down from the device between your fingers and connect them to the grounding wires on your trailer using a heat shrink, waterproof connector and hand lighter.