Trailer brakes

Trailer wiring might not be the most exciting part of hauling, but it’s one of the most important. Proper wiring ensures brake lights, turn signals, running lights, and electric brakes work reliably—keeping you legal and other drivers safe.

Common trailer wiring systems

• 4-way flat: Basic lighting (tail, stop, turn, and ground). Common on small utility trailers.

• 5-way/6-way: Adds circuits for reverse lights or brakes; used when you need more functions.

• 7-way RV blade: Standard for larger trailers and trailers with electric brakes, providing power for brakes, reverse, auxiliary power, and charging a trailer battery.

Quick checklist for safe trailer wiring

• Inspect connectors and cables for corrosion, frays, or loose pins.

• Test each light function before every trip—have someone activate turn signals, brakes, and running lights while you verify at the trailer.

• Keep grounds clean and tight; a poor ground causes intermittent or nonworking lights.

• Use dielectric grease on connectors to slow corrosion and improve contact.

• Replace damaged or brittle wiring and secure cables to prevent chafing.

• For trailers with electric brakes or charging circuits, ensure the tow vehicle’s 7-way is correctly wired and the brake controller is adjusted.

When to get professional help If you’re unsure about wiring diagrams, have recurring shorts, or need a new 7-way installed or integrated with a vehicle’s electrical system, let a professional handle it. Proper wiring and brake integration are critical for safe towing and are worth the expertise.

At Prime Tire & Auto Repair we can inspect, repair, and install trailer wiring and connectors to keep your trailer lighting and brakes functioning correctly. Stop by or call before your next towing trip to make sure everything is road-ready.