Wiring for Rear windows

[Tdehoff at aol.com]

Gentlemen:
 
I am trying to trouble shoot why my rear windows do not work.  I first  
thought it was the safety switch and I tested and I have voltage at the plug  that 
goes into the switch.  I took the switch apart and sprayed it with  contact 
cleaner and still does not work.  I also tested to see if there is  voltage at 
the plug on the back window on the driver's door and there was  voltage at the 
plug that goes to the rear window switches .  I also  unplugged the drivers 
window switch and swapped it with the rear window switch  and the rear window 
switch would then operate the drivers window and the drivers  window switch( now 
connected to the rear window) would not work.  So all i  was able to prove is 
that the switch themselves work.  I was hoping someone  could give a few 
pointers as the common reasons for the rear windows not  working.    
 
Tom in Iowa
91 200Q