13-Pin Universal Towbar Wiring Kit with Bypass Relay

13-Pin Universal Towbar Wiring Kit with Bypass Relay

This complete 13-pin universal wiring kit provides a robust and reliable electrical connection between your tow vehicle and any trailer or caravan utilising a single 13-pin plug. Designed to accommodate the complex electrical systems found on modern vehicles, this kit includes an integrated bypass relay to ensure full compatibility without interfering with the vehicle's onboard computer or bulb failure detection circuits. It supplies all essential road lighting functions as well as auxiliary power for caravan battery charging and refrigerator operation, making it a comprehensive solution for both occasional towing and extended touring.

Complete 13-Pin Functionality

The kit delivers full electrical support for all standard 13-pin requirements. In addition to essential road lighting—including tail lights, stop lights, direction indicators, fog light, and reversing light—the wiring loom is configured to manage constant and switched power supplies. This ensures that the leisure battery in a caravan receives a regulated charge while the engine is running, and the refrigerator circuit is activated only when the alternator provides sufficient power, preventing the accidental drain of the vehicle starter battery.

Advanced Bypass Relay Technology

Contemporary vehicles are almost universally equipped with CAN-Bus data networks, multiplexed wiring, or sensitive bulb failure monitoring systems. Splicing directly into rear light clusters on such vehicles can cause dashboard error warnings, dimming lights, or permanent damage to body control modules. The integrated bypass relay isolates the trailer’s electrical load from the vehicle's sensitive circuits. The relay draws a minimal signal current from the vehicle's rear lights to trigger the corresponding trailer function, while drawing the main power supply directly from the vehicle battery via a dedicated fused connection. This method safeguards the vehicle’s electronics and guarantees reliable trailer light operation.

Universal Vehicle Compatibility

This universal kit is suitable for fitment to a vast range of passenger cars, 4x4s, and light commercial vehicles. Because it operates independently of dedicated vehicle-specific ECU software, it is the ideal choice for:

• Vehicles with CAN-Bus electrical architecture.
• Vehicles equipped with LED rear lighting and pulse-width modulation (PWM) systems.
• Older vehicles without manufacturer-supplied towing preparation.
• Imported vehicles where a dedicated wiring loom may not be available.
• A cost-effective alternative to a dedicated wiring kit on vehicles outside the manufacturer's warranty period.

Versatile Towing Applications

The kit is engineered to handle the varied electrical demands of different towed units. Whether you are towing a large twin-axle caravan requiring constant battery charge and fridge supply, a horsebox with interior lighting, or a simple cycle carrier with a lighting board, the wiring provides the correct pin-out and power rating. The system is optimised for use with:

• Caravans
• Box Trailers
• Cycle Carrier Lighting Boards
• Horseboxes (including support for reversing light and interior light circuits)

Installation and Build Quality

The wiring loom is manufactured using high-grade, flexible copper cable sheathed in durable PVC insulation to withstand the harsh under-vehicle environment, including exposure to road salt, moisture, and vibration. Each wire is colour-coded and printed with its function identification, simplifying the connection process for the installer. The kit includes a pre-wired bypass relay and a 13-pin socket connector. Please note that a single-socket mounting plate or bumper bracket specific to your vehicle model is required to complete the installation and is not included within this universal kit.