Abstract: A lighting device for under-vehicle use in service and inspection locations, provides improved chemical and mechanical resistance to damage. The lighting device includes a planar light guide that is installed within a cavity of a unitary rectangular bottom support that has beveled edges and rounded corners to prevent damage during rollover. The planar light guide is illuminated with one or more LED strips at side(s) of the light guide. A transparent or semi-transparent front cover is sealed over the LED strips and planar light guide with a rectangular seal that may have a circular cross section that partially lies within a channel formed in the bottom support. The light guide is backed with a reflector and one or more diffusers may be inserted between a top side of the light guide and the front cover, which is held in place with an inset frame that fastens to the bottom support.