Lamp plugs are disclosed, in which single intensity marker lamps that are desired to be flashed can be connected to a lamp driver employing an exclusive OR (XOR) logic circuit. In one embodiment, the lamp plug is an overmolded subsystem that is installed between the lamp and the lamp driver and allows the installer to use existing wire harnesses. In some embodiments, the overmolded subsystem is installed under a standard lamp where a plug is typically plugged in; therefore staying on the vehicle and not needing to be replaced with the lamp. Other embodiments are disclosed.