Your search for "trailer connector" revealed the following:
How Electric Trailer Brakes Work — and How to Troubleshoot Them
Electric trailer brakes are a chain: the controller sends power, the wiring carries it, the magnet reacts, and the brake shoes use the rotating drum to create braking force. When trailer braking becomes weak, intermittent, uneven, or completely absent, the fastest diagnosis usually comes from finding where that chain stops...
Cold-Weather Trailer Prep: What to Check Before Fall Turns to Winter
Cold-weather trailer problems usually start before the snow does. A cord that is already stiff, a junction box that already holds moisture, a weak breakaway battery, a leaking grease seal, or a corroded light connection may work through summer and become the failure you notice after the first freezing night....