Having just returned from our maiden voyage in our 2006, Autotrail Tracker SE we are delighted with the experience and look forward to many such ventures. Our only minor niggle was that the waste water indicator stayed showing 0% for the whole of our three days away despite going through a full tank of fresh water, most of which would have ended up in the grey waste. Is this likely to be a failed sensor? I am reasonably competent mechanically so would be happy to try and replace it myself if possible but don't actually know where the tank is... And while I have your rapt attention, could anyone enlighten me as to the whereabouts of the external awning light switch? Hunted high and low but can't find it... Many thanks, Jerry.