I have an 03 Ford Focus. The driver side master window switch and the front passenger window switch both work perfectly. Both rear passenger switches work about 1 out of 1000 tries. I can put both the rear passenger windows down with the master switch.

Because I can roll down the rear windows from the front I thought that meant that the rear switches were broken (and not the motor). I ordered a new switch online, installed it... they still don't work. I thought maybe they sent me the wrong switch so I tried it in the front passenger area and it works fine.

Now I'm flabbergasted. Is there a fuse for this or could it be the wiring? I'm really just guessing randomly now

 

Door window switches can be a little confusing since all switches have to to be in working condition for the system to operate properly. Did you try the switch on both sides in the rear? The system chris crosses the switches and if one part of any switch is defective a problem shows up.