The Key Start Switch is a three position switch with two inputs into the ECM. When the Key Start Switch is moved to the ON position, a system voltage input is provided to the Machine ECM. The presence of this voltage input will cause the ECM to transition from the "sleep mode" (inactive) to the operational mode. When this mode change occurs, the ECM will initialize and then become operational.
When the Key Start Switch is moved to the OFF position, the system voltage is no longer present at the ECM "Key Switch - ON" input. The absence of the system voltage signals to the ECM to transition from the operational mode to the sleep mode. The ECM will perform some internal power down procedures and then enter the sleep mode.
The transition period from the sleep mode to the operational mode happens in a short time. When the Key Start Switch is moved to the "START" position, a system voltage input will be provided to the Machine ECM start contact. When the ECM detects the voltage in the circuit and the machine systems start status is correct, the ECM will initiate the engine cranking sequence.
The key start switch circuits are not monitored for diagnostics by the Machine ECM.
The operator presence sensor is located in the seat cushion for the operator seat. The sensor is an analog voltage sensor that varies with pressure.
The cab removed sensor is two circuits in the wiring harness that will be interrupted if the cab is removed. In this way the ECM is alerted if the cab has been removed from the machine.
The main power relay is controlled by the machine ECM. When the keyswitch is moved into the ON or START, the ECM energizes the main power relay. The relay provides power from the battery to all switched systems.
Front, Left, and Right Wiper Switches
Front, Left, and Right Wiper Relay
The left and right wiper relays are energized by the machine ECM. The relays control the operation of the left and right wiper motors.
The flood light switch controls the flood lights and sends a signal to the ECM indicating that the lights are either on or off. When the lights are turned on, the display is dimmed.