A towing trailer can hold various items, from a boat to a small car. Typically, a pick-up truck or a large car pulls a towing trailer, attached together by a hitching system. In the past, the towing trailer's lights, from brakes to turn signals, were hard-wired into the towing vehicle's electrical system. Wiring harnesses connected between the tow vehicle and trailer to supply the necessary lighting power. As a result, the vehicle and trailer tail lights illuminated in unison during a drive, clearly notifying surrounding motorists when the vehicle combination would brake or turn.
The U.S. Department of Transportation stipulates that a towing trailer must have turn signals, side and rear reflectors, side marker lights and brake lights, under federal law. The lighting can be either hard-wired or portable, as long as it reliably operates during a drive. However, some local and state laws may apply variations to the federal laws. Drivers should contact their local authorities before a long towing trip to verify specific state lighting laws. Verification can help a driver avoid an infraction ticket down the road.
Modern portable lights typically use magnets to adhere to a tow trailer, or even to the item being towed. Depending on the model, wires extend from each portable light, such as the left and right brake lights, to the towing vehicle's electrical wiring harness. However, newer portable lights are available that use wireless technology. A radio transmitter plugs into the towing vehicle's electrical wiring harness. Magnetic lights are placed along the towing trailer. As the driver brakes, a radio signal emits from the towing vehicle's electrical system, activating the wireless lights for illumination. These wireless portable lights are especially helpful if a driver has various towing trailers, or items, that are towed periodically. The lights move easily from one trailer to another.
A towing vehicle's wiring harness configuration may vary between different car manufacturers. Verify that the vehicle's wiring harness is compatible with the trailer's connection. You may need a tail light converter to convert an incompatible connection.
