Unfortunately, I don't have any other cars to test the display in, but the one I bought on ebay was working I was assured. It's the same problem with either one.

I've also tried pulling the blue plug from the TV unit and plugging directly into the GPS which was a suggestion on another board - still nothing.

I'm not quite sure where to go from here. I guess I need a wiring diagram.

Someone on yet another list reckoned that jump starting can kill the systems, but there's an inline surge protector between the GPS unit and something else that is easily fixed as a result of voltage spikes due to jump starting (I had to do this many times - the unit stopped working at the same time).

Have you heard of this?