Brake Pedal Switch: Notes
The cruise control ECU has two inputs from the brake pedal switch that determine the position of the brake pedal. See Fig 1. One input comes through the BCU and is low when the brake pedal is not pressed. The second input comes directly from the brake pedal switch. This input is high when the brake pedal is not pressed. On vehicles with a manual gearbox, the input from the clutch pedal switch to the cruise control ECU is connected in series with the direct signal from the brake pedal switch.
If the cruise control ECU receives a changed signal from either source, it deactivates cruise control, removing power to the vacuum pump and activating the vacuum control valve releasing all vacuum in the system.
The brake pedal switch also provides the signal to illuminate the brake lamps and the brake input to the SLABS ECU.