Don't despair it might not be the light. Mine also stopped working, I thought it was the light but on further inspection it proved to be a corroded terminals in a nylon connection box situated at the rear of the van inside the rear plastic 'bumper' trim. Chopped off the wires and reconnected them fortunately there was sufficient slack to do this. I feel that the rear bummer was acting as a scoop to allow water/spray to get to the connection box so the joined wires have been waterproofed and secured up out of the way.

Is the 'B' word allowed?

Thank you for that Grandpa P 😊