F 350 4WD Pickup V8-351 5.8L VIN H EFI (1997)
Brake Light Switch: Description and Operation
The electro-mechanical stoplight switch, installed on the pin of the brake pedal arm, straddles the push rod of the power brake booster but is not attached
directly to the push rod. The stoplight switch is located near the brake pedal arm. The stoplight switch moves with the pedal arm when the brake pedal is
depressed.
The stoplight switch actuating pin is held by spring pressure against the rear end of the power brake booster. Because of the slight clearance between the
eye of the push rod of the power brake booster and the brake pedal arm pin, the pin and the stoplight switch move forward slightly before the push rod
moves when the brake pedal is depressed. This relative movement between the stoplight switch and the end of the push rod moves the actuating pin
rearward in the stoplight switch, closing contacts on the stoplight switch completing the circuit to the rear lamps.
When the brake pedal is released, the stoplight switch moves rearward in relation to the push rod. The spring in the stoplight switch returns the actuating
pin to its normal position, opening contacts on stoplight switch and interrupting the circuit to the rear lamps.
