I have a 2001 Bailey Senator fitted with a Thetford C-200 CW. It works fine except on the last outing the red/green indicator for the waste container didn't work. I have changed the batteries for new, and checked the wiring that I can see which all seems fine. Does anyone have any ideas why the indicator has suddenly had a hissy fit? Is it an easy repair or do I just have to keep an eye on the level from now on?