Vacuum Cleaners Discussions

Hey  everyone... I thought it would be fun to add a self propelled windtunnel to my collection since my big lots had them for 100 dollars factory refurbished.  Well, it's been nothing short of a nightmare hitherto... it was missing the crevice tool, deeply scuffed, and the power drive doesn't work right.... first it wouldn't go forward, and now it reverses when turned off.  Give my a concept any day (keep the dialamatic though, don't like them)....  I had to vacuum for an hour with my power drive concept just to get the bad taste out from this windtunnel nightmare and use a real machine again.

Anyway, another problem, as if there weren't enough already is that the dirt sensor light always stays red... even if I lift the vacuum up off the carpet so there's no possible way for dirt to be entering the machine.  I know the Kenmore/Panasonics used an infrared sensor right where the hose enters the machine... and I've heard that the Hoover instead uses a microphone, but where in the world is it located in the vacuum and is there a way to clean it so it works properly?  Hopefully this is advice I don't need as I'm going to exchanged the machine tomorrow for one that works right, looks good, and has all the parts... but if I'm going to own this vacuum, it's probably something I should know. 

Thanks!