A motor vehicle lamp assembly (10) having a lamp bulb (12) for emitting light and a bulb housing (14) having a light transmissive portion (16) for transmitting light from the lamp bulb to an illumination zone. The housing is coated with a coating material (60), which covers a selected region (32, 34, 36) of the light transmissive portion of the housing. The coating material is electrically energized to alter an amount of light transmitted from the bulb to the illumination zone. A drive circuit (30) electrically coupled to the coating material energizes the coating material to control a light output from the lamp assembly.