1998 Buick Riviera Owner's Manual - Page 100

Express-Down Wmdow Switches on the driver's asmrest control each of the windows while the ignition on or retained accessory is power is active. In addition, the passenger's door armrest has a switch for its own window. To lower the passenger's window, back=onthe fight pull switch. The window lower as long as the switch.is will held. To raise either window, push the switch forward.