Illuminated signs for vehicles, mounting systems therefor and related methods

A self-contained illuminated sign for direct or indirect mounting on a vehicle, the sign comprising:

• a front panel;
• an opaque rear panel situated opposite and substantially parallel to the front panel in spaced relation therefrom to define a space therebetween;
• and
• a light source comprising a plurality of LEDs and a diffusion panel to diffuse light emitted by the LEDs, the light source being positioned in the space between the front and rear panels and configured to emit light that emanates from the front panel, wherein the diffusion panel is substantially parallel to the front and rear panels and is sized smaller than the front and rear panels to define a channel between the front and rear panels and along the perimeter of the diffusion panel;
• and
• a weather-tight seal disposed in the channel, the weather-tight seal wrapping around the perimeter of the diffusion panel and having a width spanning the distance between the front and rear panels to seal the space therebetween.