Where is brake light switch on a 1986 Cutlass?
There should be a bracket mounted on the steering column near
the floor. This will have a switch in it that is a plunger type.
When the shaft of the brake pedal is depressed, it comes into
contact with this plunger and activates the brake light circuit. If
you "ride the brakes", your brake lights will always be on because
of the minimal pressure required to activate this circuit.