Lift gate power control system

A lift gate ( 12 ) is raised and lowered on a motor vehicle by a prime mover. An electrical system of the vehicle has at least one D.C. storage battery ( 22 ) for raising and lowering the lift gate when the vehicle engine is not running. A disconnect, such as a mag switch ( 20 ) carries electricity from the battery to the prime mover when actuated to an enabling condition. Control logic for selectively enabling and unenabling the disconnect to carry electricity to the prime mover from the battery includes a control input ( 28, 32 ), a source providing battery voltage data corresponding to actual battery voltage ( 26 ), and a timer in an ESC ( 24 ). The control logic causes the disconnect to become and remain enabled upon the control input requesting enablement of the disconnect and battery voltage data indicating actual battery voltage in compliance with a defined criterion until the earlier occurrence of 1) elapse of a length of time set by the timer and 2) battery voltage data disclosing non-compliance with the defined criterion.