Braking Sensor/Switch: Description and Operation

BRAKE LAMP SWITCH (BLS)

This switch prepares the CAB for a possible antilock event. The CAB uses an output state voltage from the BLS when the brake pedal is either depressed/released. The Fused Ignition Switch Output circuit supplies 12 volts to the BLS. A depressed brake pedal will close the BLS circuit and the BLS Output circuit supplies 12 volts at the CAB. When the driver releases the brake pedal, the BLS Output circuit voltage drops to 0 volts and the CAB senses the brake pedal state. This tells the CAB what position the brake pedal is currently in to make an ABS event possible. When using the DRBIII in Inputs/ Outputs, the BS and BLS will read opposite switch states. Note: The BS and BLS are in the same switch housing.