Replacing a worn-out four-wire trailer plug is a quick and easy job. Step 1: Use a pair of diagonal pliers or a wire cutters to remove the existing plug from the trailer. Step 2: Take the old plug end ...

The Rated Red Crew swaps trailer lights faster than a pit crew, and somehow makes wiring look easy.

This is the primary cause of trailer-light problems. Symptoms include flickering, fast-blinking, dimness, intermittent operation (often when a trailer ball is used for a ground), and complete failure.