My back up lights are not working even though all other blinkers and lights are. I checked the bulbs and fuses but all seems ok with those, any ideas anyone?

Also, for a couple years now my vent system fan would only work on the highest speed so I was alwasy blasting it then turning it off to regulate. Now it's starting to just cut off when it's on, then I turn it off for a minute then turn it back on (on the highest level) and it works again. I've heard it's a switch and it's easy to fix, I just don't know where to look. Any directive is most appreciated.

Thanks