Pressure Switch

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1988 Oldsmobile Ninety-Eight, 1988 Oldsmobile Delta 88, 1987 Oldsmobile Ninety-Eight, 1987 Oldsmobile Delta 88, and 1986 Oldsmobile Ninety-Eight. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Before servicing any component which contains high pressure, it is mandatory that hydraulic pressure in the system be discharged. With ignition off, pump brake pedal a MINIMUM of 20 times using full pedal strokes. When a definite increase in pedal effort is felt, pump pedal 2 more times.

Turn ignition off. Discharge system pressure. Disconnect negative battery cable. Disconnect electrical connector from switch.
CAUTION: Failure to remove connector can result in damage to connector if pressure switch wrench handle should slip and strike connector.
Remove pressure switch using Pressure Switch Remover (J-35804). To install, reverse removal procedure. Turn ignition on. "BRAKE" light should go out within one minute.