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.
If you're hauling a boat, chances are you've dealt with rusty, dim, or broken trailer lights. Upgrade to these bright LED ...
Order Led Submersible Trailer Light Kit Submersible LED Trailer Tail Lights Kit - Waterproof With 25-Foot Wire Harness Travel ...