89 ford mustang gt convertible

all the power windows only work from driver's control switchboard.
I've checked the "unlock" button and it is allowing the 12 volts to pass through.
where does that wire go to?
I opened up the passenger switch and it seems to work via "ground" passing through but there is not positive 12 volts going through. Is it supposed to have volts go through or do the switches work on the "ground" wire?
help!