All 4 Power Windows quit....
 

My mother in law's 2000 300m has a sudden problem that I can't track down. Suddenly, all 4 power windows have stopped working. Luckily, they are all up. I haven't been able to find a blown fuse anywhere. I found the relay for the windows just above the power seat relay; they're the same, so I swapped them but that didn't change anything.
It's as if the relay isn't getting power, so I'm wondering if it could be a breaker or fuseable link somewhere?
Someone suggested the driver's window control panel....but none of the individual window controls on the doors work either.
Yes, I could take it to the dealer but I'm trying to save my mother in law the $75 diagnostic fee :)

I love this car....it only has 35K miles on it.

Any thoughts?
Thanks!

Check for Power and ground at the master drivers control....Everything branches out from there.

Thanks :) I'll report the results here.