GEAR-BEVEL 4E7159 - Caterpillar

Illustration 11 g03325168The secondary steering test switch is a single pole switch. The switch alerts the ECM that the operator would like to test the secondary steering system. The contact on the ECM for the secondary steering test switch floats to a high voltage state when the switch is open. When the switch is activated and the switch closes, the ECM contact is pulled into a low or ground voltage state.Left Hand Joystick
Illustration 12 g03868218The left-hand joystick contains a neutral centering switch that has a normally open and a normally closed contact. The normally open contact normally floats to a high voltage state and the normally closed contact is pulled to a low voltage state. When the switch is engaged the normally open contact closes, and is pulled to a low voltage state and the normally closed contact opens, and floats to a high voltage state.Outputs
The ECM responds to decisions by sending electrical signals to the outputs. The outputs can create an action or the outputs can provide information to the operator or the service technician.Relays
Secondary Steering Relay
Illustration 13 g03324979The secondary steering relay provides power to the secondary steering motor. The ECM can send a signal to the relay causing the relay to energize. When the relay is energized, battery power is sent to the secondary steering motor.Proportional Solenoids
Illustration 14 g03552417All proportional solenoids in the steering system are identical in construction, however function differently. Illustration 14 shows an example of a proportional solenoid in the steering system.Note: The solenoid coils are not designed to operate using 24 DCV directly. The ECM sends a PWM signal of 24 V at a duty cycle that will provide the necessary current to the solenoid coils. Do NOT activate the coils by using 24 DCV (+battery). The life of the coils will be reduced drastically. A source of 12 DCV should be used, if the coils must be activated by not using the ECM. Primary Steer Right/Left Solenoids
There are two solenoids controlling the primary steering system. There is a right and left solenoid. The two solenoids are identical in construction, and together control the primary steering spool. The solenoids are proportional solenoids, and if the ECM sends a higher duty cycle signal to the right solenoid, that solenoid shifts the spool further in the RIGHT position. If the ECM sends a higher duty cycle signal to the left solenoid, that solenoid shifts the spool further in the LEFT