What is the function of the breakaway switch on a trailer?

The function of the breakaway switch on a trailer is to activate the trailer brakes if it becomes disconnected from the towing vehicle. This safety feature is designed to prevent the trailer from rolling away uncontrollably in the event of a separation from the tow vehicle.

When a trailer detaches, the breakaway switch pulls a pin or lever connected to the trailer's braking system, which engages the brakes immediately. This action greatly reduces the risk of accidents or property damage that could occur if a trailer were to roll freely on its own. The breakaway system is a vital component in maintaining safety while towing, ensuring that the trailer remains under control even if it becomes disconnected.

The other options pertain to functions that are not relevant to the specific role of the breakaway switch, such as reducing sway, improving fuel efficiency, or monitoring tire pressure, none of which are functions of this particular safety feature.