A headlamp assembly for a motor vehicle is disclosed as having a light source, a chamber within which the light source is located, and a cooling channel extending through the chamber. The chamber substantially fluidly sealed from the atmosphere and the cooling channel is fluidly sealed from the chamber to prevent direct fluid exchange between the chamber and the channel. Heat exchange, however, is permitted between the chamber and the cooling channel. The heat exchange may be further promoted by a plurality of heat exchange fins extending away from the wall of the cooling channel.