Led Shift Light Plugs-In Directly To All s For An Instant Shift Light. Needs Rpm Modules To Set The Rpm MSD IgnitionThe MSD Shift Light will turn on to remind you to shift when the engine reaches your specified rpm. You select the rpm using the same plug in modules that are used with your MSD Soft Touch Rev Control. The Shift Light features a bright cluster of LEDs making it easily visible, even in bright daylight. The light will also turn on for a second or two when the ignition switch is first turned on to inform you that the light is functioning properly. The