Oyviny 7-Pin & 4-Pin Trailer Plug Tester with Double-Sided LEDs

Two-in-one trailer tester for 4-pin and 7-pin connectors

The Oyviny trailer plug tester combines a 7-pin RV blade and a 4-pin flat tester in a compact, easy-to-use device. It’s designed to help you verify wiring on the go, whether you’re hitching a boat trailer, RV, or utility trailer. Important note: it does not work with vehicles that have a lamp-out sensor.

Clear, readable indicators

Each function is represented by a dedicated LED, and the tester features double-sided indicators for easier visibility from multiple angles. This design helps you quickly confirm which wiring path is active, reducing guesswork when you’re under the hitch or inspecting a connector on the side of the road.

• Taillights
• Brake lights
• Reverse lights
• Turn signals
• Electric trailer brakes
• 12V auxiliary power

Build, durability, and ease of use

Manufactured with durable ABS plastic, the tester resists rust and corrosion for long-term use. Tin-plated copper terminals ensure solid conductivity, while the compact, battery-free design makes it ready for quick checks anywhere you park or connect a trailer. The ergonomic shape makes plugging in and unplugging feel natural, even when you’re working from a tight space at the hitch.

Key benefits you might experience include faster troubleshooting, clearer insight into which circuit is at fault, and a streamlined way to verify that your trailer wiring matches your vehicle’s functions before you hit the road. This tester is suitable for testing trailer light circuits on most trucks, boats, trailers, campers, caravans, and food vans, and it’s compatible with both 7-blade RV connectors and 4-pin flat plugs.

How to use

1. Plug the tester into the trailer connector (7-pin or 4-pin).
2. Operate the vehicle’s lights and observe the LED indicators.
3. If an LED stays off or a function doesn’t light, review the wiring or connector alignment and retry.

Why choose Oyviny

This tester offers a practical, non-invasive way to assess trailer wiring without extra tools. It’s designed to be a reliable companion for DIY trailer maintenance, seasonal checks, or while setting up new trailer configurations. While it aims to help you identify potential issues, it doesn’t guarantee fixes, and results may vary with certain vehicle systems.