Purkeys Fleet Electric has developed what it calls a 5th Wheel Light that illuminates the jaws so drivers can see that they've grabbed onto the trailer's king pin, which should reduce incidents of dropped trailers.

The 5th Wheel Light is a compact box that mounts to a crossmember, off to one side and facing forward toward the fifth wheel. The light is wired into power and ground circuits, and into the circuit for backup lights or alarm. It illuminates when the driver shifts the transmission into reverse and stays on for a preset time, usually five to 15 minutes, then automatically shuts off. 

The LEDs shine into the fifth wheel, eliminating shadows on the locking mechanism and reduce the need for a flashlight, according to the manufacturer.