Modern vehicles come packed with sophisticated electronics that make driving safer and more efficient, but these same systems can be incredibly delicate when it comes to trailer wiring. Traditional towbar connections can overload sensitive control modules, trigger warning lights, or even cause permanent damage to your car's expensive electrical systems. That's where the AB Tools Smart TR186 bypass relay comes in - specifically engineered to bridge the gap between your car's advanced Canbus multiplex wiring and your trailer's lighting requirements.
What makes this relay truly special is how it isolates your vehicle from potential trailer electrical faults. The relay connects directly to the back of your vehicle's lights just like traditional towbar wiring, but then powers the trailer lights directly from your battery. This clever design means your car's lighting system draws only 0.001A (that's 1 milliamp - less than what a single LED bulb uses), completely avoiding any interference with bulb warning systems or sensitive electronics. Whether you're driving a brand-new car with integrated lighting systems or an older vehicle with shared wiring for sidelights and brake lights, this relay handles it all.
Installation is refreshingly straightforward, especially if you've ever wired a towbar to older vehicle lights. The provided wiring guide gives you everything you need - color-coded wires for each function: yellow to left indicator, blue to fog light, white to earth, green to right indicator, brown to right tail light, red to brake lights, black to left tail light, and grey to reverse light. On the relay itself, you simply connect each terminal to the corresponding trailer pin. The system also includes an audible warning buzzer for trailer light operation, a feature now tested and accepted in MOT inspections across the country.
Whether you're towing a caravan for a family holiday, carrying equipment for work, or transporting boats and trailers, this relay ensures your vehicle remains protected. It handles everything from trailer short circuits to electrical overloads, safeguarding your car's expensive control systems while providing reliable trailer lighting. The fact that it works with vehicles where sidelights share wires with brake lights or fog lights means it's compatible with virtually any modern car on the road today. Install it once and enjoy years of worry-free towing, knowing your vehicle's sophisticated electronics are completely shielded from trailer electrical issues.
