An electric power source supplies electrical power to an electric machine of a vehicle via a plurality of high voltage lines. A plurality of connections are disposed within a housing for connecting the high voltage lines. A cover member encloses a hidden magnet and is removably secured to the housing so that removal is necessary to obtain access to the high voltage lines. A reed switch is mounted proximate the cover member, when secured, within a magnetic field of the magnet, whereby the reed switch is closed when the cover member is secured and is open when the cover member is removed. A controller is controllably coupled to the power source via a control connector and circuit of the electric machine. Such circuit extends from the reed switch to the controller, where the controller causes the electric power source to stop supplying electrical power when the cover member is removed.