Front passenger window not working from passenger switch only

The front passenger window on my 2000 Lincoln Town Car stopped working from the passenger switch. The driver switch operates the window without any problem. I removed the switch and cleaned the contacts and this did not fix the problem, so I tried to check voltage to the switch. I'm not getting any voltage when I connect the Up wire to ground or the Down wire to ground. I'm not sure what to do with the fifth wire in the harness (labeled B+ on the switch), and I'm afraid to try to check voltage on this wire until I know better what it does.