System designed to detect a left jumper the moment it is being left. The Dash and Rack Units (coupled by a 25ft cord) are installed in the maintainer’s truck. When installed properly, power is applied to the System when the vehicle ignition switch is turned on. If one or more jumpers is not re-attached to the Rack Unit, an 80dBA audible alarm immediately triggers, jolting the maintainer into remembering that a jumper was not returned to its place on the Rack Unit. Without any additional measures required, save routine maintenance, the simple act of using a jumper sets in motion an alarm that will remind the person who left a jumper that he should go back and get it. Rack Unit capacity is six jumpers. For circumstances where a jumper capacity in excess of six is required (e.g. following a T & S gang), Extension Rack Units are available to add jumper capacity in multiples of six. Up to five Extension Racks can be added to the original Rack Unit. System operates on a nominal 12 VDC (truck battery).