More than just aesthetics though, the backlighting is used to alert you to any potential issues and whether everything is functioning properly to keep you safe. For instance, when the Ignition switch is pressed three color states verify that everything is working correctly. When the contactors are open there is no backlight, and when the pre-charge process begins the backlight turns yellow. Once the pre-charge process is complete and the contactors close the backlight turns green to notify you that the vehicle is safe to operate, and if a fault is detected the backlight turns red.
EV programmable button pad for use with VCU200 or VCU300