ENGINE AR-COMPLETE 3730058 - Caterpillar

Illustration 15 g01329042
starter keyswitch input circuits
The Transmission/Chassis ECM monitors the status of the starter keyswitch. When the starter keyswitch is in the ON position or in the START position, a system voltage input is supplied to the ECM through the contacts of the key switch. When the Transmission/Chassis ECM detects the system voltage at the START input, the ECM will activate the start relay in order to initiate the engine start process provided the following machine conditions are present:
The parking brake is engaged.
The transmission is in NEUTRAL.
The operator is in the seat.Left Joystick Transmission Control Inputs
Illustration 16 g01329215
Left Joystick Transmission Controls
(8) Upshift push button switch
(9) Downshift push button switch
(10) Forward/neutral/reverse trigger switch
Illustration 17 g01329216
Left Joystick Transmission Control input circuits
The illustration above shows the internal push button and ground assignments for the transmission controls in the left joystick. The components that are in the left joystick are not serviceable. If a component in the joystick has failed, the complete joystick assembly must be replaced. The illustration is displayed in order to aid in the component and circuit troubleshooting for the transmission controls. For a complete connection diagram for all of the joystick to ECM connections, refer to the System Schematics in the back of this manual.The upshift switch, the downshift switch and the FORWARD/NEUTRAL/REVERSE (FNR) switch provide switch to ground inputs to the Transmission/Chassis ECM in order to indicate operator commands for gear selection. Each switch is internally connected to two of the four ECM return (ground) circuits that are supplied to the left joystick. One of the ECM return circuits for the switches is supplied by the Transmission/Chassis ECM and the other ECM return circuit for the switches is supplied by the Implement ECM. Both ground connections would have to fail either internally or externally in order to interrupt switch operation due to loss of ground connections.The ECM expects one of the switch inputs to be grounded at all times. If all of the switch inputs are grounded or if none of the switch inputs are grounded, the ECM will activate a diagnostic code for the switch.Park Brake Switch
Illustration 18 g01379168
Rocker Switch Contacts
Illustration 19 g01379171
Parking Brake Switch input circuit
The parking brake switch provides a switch to ground input to the Transmission/Chassis ECM. The switch is a two pole, double-throw rocker switch. The switch is located on the right hand console in the cab.One pole on each of the switch is used to provide the input to the ECM in order to indicate the switch status. During normal operation, one of the inputs is open and the other input is closed to ground. If the ECM detects that both of the switch inputs are grounded at the same time or both of the switch inputs are open at the same time, the ECM will activate a diagnostic code for the involved switch.For the operation of the parking brake switch, when the ECM detects a ground condition in the "ON" switch input circuit, the ECM will deactivate the parking brake solenoid in order to engage