Could someone help ?Recently, I tried connecting an power invertor to the 12 volt supply but could not get power via the outlet on the instrument panel. I checked the back connections and all appeared OK. I did get it working but the next day the same problem. I thought I had to insert the plug in a certain way but this should not make any difference.Normally these plug sockets work well.Any advice would be appreciated.Cheers,Dave Roche