Thanks for visiting Just Answer, the master switch controls the windows, locks and mirrors, when you replace the master switch you are replacing that whole part as an assembly. It's a really easy repair you should try to make. Click here for instructions
Would this also have anything to do with the car not starting some times. About every other week the car just won't start. New battery, etc. We disconnect the cables, reconnect then and the car works fine for the next couple of weeks. Is this also due to the bad master controller (switch)
No, these are going to be different issues. this car is known for passlock or security issues for causing intermittent no starts.
The master switch is something you should fix yourself.
A security problem should really be left up to the dealer.