A year ago the driver side power window wasn't working. Passenger
side OK. Replaced the master window switch with an aftermarket unit:
problem solved. ...at least for a few months.

Last week, BOTH windows stopped working from the master switch, and
the passenger window wouldn't work from its switch, either. But when
either switch is pushed in either direction, I can hear a faint click
from inside the door panels.

The driver/master switch shows 11.5V input (on small digital
multimeter) and a good ground to chassis (as measured on an analog
Simpson 260 ohmeter). When I operate the switch, the respective
outputs show 9.5 volts. They're all there, on the correct output
wires, when the given switch is pushed. All I get is the soft click,
no motor operation on either door. The power door locks work fine.
Any ideas?