Rectangle trailer lights keep your rig tidy and easy to see. Choose LED or incandescent, with submersible options for boat trailers and 3-prong triangular plugs to match existing wiring. Check measurements and mounting style so replacements line up with tail, side marker, fender, or license plate light locations.
Installation is typically straightforward and can wire directly into existing light wiring. If your hardware uses a carriage bolt in a plastic track, avoid nyloc nuts so the bolt doesn't spin. If your trailer originally used a chassis ground and you're seeing issues, switch to dedicated grounds to each light to improve reliability.
Yes, choose rectangle lights listed as submersible with a waterproof or sonically sealed housing. Some folks disconnect the lights before launching and reconnect after leaving the ramp. Filling pigtail sockets with dielectric grease can help keep water out. If you see moisture inside a housing or corrosion on contacts, recheck seals and wiring before the next dunk.
Confirm the connector style first; some rectangle tail lights use a 3-prong triangular pigtail. For a lighted license plate bracket with a 4-way, connect the black wire from the bracket to the brown wire on the 4-way, and the white to white. If your trailer is bolted together, running dedicated grounds instead of a chassis ground can help.
Measure the light's length, height, and depth, and compare to your opening. Common rectangle tail lights come around 6" x 3-1/2", and some older units are about 7" x 3-3/4" x 3" deep. If a specific contour or wraparound lens isn't available, consider updating to a similar-size LED assembly and verify the mounting method lines up.