ELECTRICAL SYSTEM CONTINUED
Proportional Brake Solenoid
Refer to Table 5.
The ECM uses the brake proportional solenoid to engage or disengage the service brakes. It receives a PWM input
signal from the brake pedal position sensor and outputs a proportional PWM signal to energize the solenoid. The
ECM will control the amount of electrical current that is sent to the solenoid depending on the position of the brake
pedal. The service brakes are spring applied and hydraulically released.
Figure 19. Proportional Brake Solenoid.
When the machine is operating and the service brake pedal is not depressed, the ECM will send the maximum
current to the solenoid in order to disengage the service brakes. As the brake pedal is depressed, the ECM will
DECREASE the current signal to the solenoid, which will cause the brakes to be applied. As the travel of the brake
pedal is increased, the ECM will continue to DECREASE the current signal that is sent to the solenoid. This will
cause the service brakes to increase the force of engagement.