Power Windows - 3 quit at once
 

Three of my 89 300E's windows stopped at the same time. The only one that works is the one whose motor I had replaced.

Any ideas?

That is highly unusual. I remember an old benz I had where the fuse would burn out and the left rear and the right front would not work. If you have already checked your fuses start at the swtich to ensure you are getting power to the switch and from when you click it, if you are ok there then go to the motor, if you are getting power to the motor, then it is your motor. Good luck!
Brian