Abstract: A back-lighted illuminated sign includes a vented light sign cabinet having a light-transmitting front panel , with two side panels, top panel, a bottom panel, and a rear cabinet panel enclosing a cabinet interior having a light source contained therein and wherein said bottom panel includes passive vent openings for admitting a thermally induced draw of cooler ambient air flow there through into the cabinet's interior. The rear cabinet panel includes vent openings arranged adjacent the top panel, for exhausting thermally-induced air flow, at a first temperature, from the cabinet's interior. The cabinet includes spacers for spacing the cabinet from an adjacent freezer in chimney defining relation between the rear cabinet panel and an adjacent exterior panel of the freezer, with air flow admitting and exhausting openings at the lower and upper ends, respectively, of that chimney.