> The switch of which you speak is tripped by an imbalance of pressure
> between the front and rear braking systems.
Later cars have a dual master reservoir and the differential switch
of which you speak. The brake lights are activated by a pushbutton-
style switch mechanically activated by a tab on the brake pedal,
up and under the dashboard.
Earlier cars have a single master reservoir and a hydraulic switch
to activate the brake lights. This hydraulic switch is screwed
into the distribution manifold. It is not a differential switch, though
it can be mistaken for one. This also means that there is no mechanical
switch activated by the brake pedal.
-- John
John F Sandhoff sandhoff@csus.edu Sacramento, CA
|