I cannot get the rear windows on my convertible 99 to go up or down. I have power, the motors work with external power, the switch sends current to the motor, but the when I activate the switch, I hear a faint click and nothing else happens. This is on both sides, exactly the same symptoms.

motor is probably busted

Does your passenger window go down?? If not, check your window lock.
IT is on the drivers side arm rest. Mine got clicked on and I was in a panic that the windows would not work. Hope this helps!!!