0340767 JOHNSON NIPPLE, Lower drain

Block Diagram For Ride And Engine Fan Control SystemThe ride and engine fan control system electronically controls the activation of the ride control system and/or activation of reduced speed for the engine fan. There are three different configurations of the ride and engine fan control system. Each configuration uses only the required components. The three configurations are.* Ride Control Only* Engine Fan Control Only* Ride Control And Engine Fan ControlComponents Description
For reference, see the System Schematic at the end of this manual.Ride/Fan Control
Ride/Fan Control
(1) Display. (2) Connector. The ride/fan control makes decisions based on input and memory information, then the corresponding response is made through the outputs. The inputs and outputs of the control are joined to the machine harness by connector (2) which has 40 contacts. Display (1) shows diagnostic information for troubleshooting the ride/fan control system.Inputs
Numerous inputs inform the ride/fan control of the status of the machine conditions. The inputs are switch type inputs. Switches provide an open, grounded, or +battery signal to the switch inputs of the ride/fan control. The inputs are listed on the Contact Description chart.Outputs
The ride/fan control responds to decisions by sending electrical signals through the various outputs. The outputs either create an action or provide information. The outputs are listed on the Contact Description Chart. In addition, display (1) is an output of the ride/fan control.Input/Output
The CAT® data link is used to communicate with other electronic control modules on the machine. The CAT data link is bidirectional; which allows the ride/fan control to receive and send information. See the topic CAT® Data Link.Switches
Switches provide an open, ground or +battery signal to the switch type inputs of the ride/fan control. Switches are two state devices; either open or closed.* When a switch is open, no signal is provided to the corresponding input of the ride/fan control.* When a switch is closed, either a ground signal or +battery signal is provided to the corresponding input of the ride/fan control.Air Conditioner (A/C) Circuit
Partial Air Conditioner Circuit DiagramThe air conditioner (A/C) circuit is an input of the ride/fan control and connects to connector contact 18. The control monitors the status of the air conditioner circuit. In order to perform the fan control function, the control must know if the air conditioner is ON or OFF. Also see the topic Ride Control Operation.A harness splice located near the A/C pressure switch (which is mounted by the A/C compressor) joins the air conditioner circuit to a switch input (contact 18) of the control. When the blower switch is in an A/C ON position, a +battery signal is present at connector contact 18 of the control. When the blower switch is NOT in an A/C ON position, a ground signal is present at connector contact 18 of the control (the circuit is grounded through the clutch solenoid).Ride Control Switch
Ride Control Switch The ride control switch is an input of the ride/fan control and connects to connector contacts 15, 16 and 17. The purpose of the switch is to tell the control which ride control mode (ON, OFF or AUTO) the operator has selected. Also see the topic Ride Control Operation.The ride control switch is a three position rocker switch. Three terminals of the switch connect to the ride/fan control. The control watches the terminals of the switch for certain combinations of open and ground signals. See the Ride Control Switch Status chart. The control diagnoses certain failures in the circuit of the ride control switch. If an invalid combination of opens and/or grounds exist, the control knows a circuit failure is present. This fault is then shown on the display of the ride/fan control; see the topic Diagnostic Operation.Service Switches
Service switches are not necessary for viewing ride/fan control diagnostics. The diagnostic information for the ride/fan control is available on CMS. For more information, see service manual SENR5247 "Computerized Monitoring System (CMS) With VFD Circular Gauges".In order to view and clear the diagnostic information at the ride/fan control, a service box is required; see the Testing And Adjusting section. The service box connects to the service and clear inputs (connector contacts 24 and 25) of the control. The proper combination of open and/or ground at these inputs performs the diagnostic functions; see the topic Diagnostic Operation.Options Plug
The options plug is an input of the control and connects to connector contacts 20 and 21. The purpose of the options plug is to tell the control how the machine is configured; with ride control system components, with fan control system components or with both.The ride/fan control operates in a manner that corresponds to the open or grounded state of connector contacts A and B of the options plug. The control interprets the status (open or ground) of connector contacts A and B and then functions accordingly. See the Options Plug Status chart. Connector contact C of the options plug is always connected to frame ground. The connections of the options plug are intended to be permanent. The options plug is part of the machine harness and is located near the ride/fan control.Ride Control Solenoid Valve
Ride Control Solenoid ValveThe ride control solenoid valve is an output of the ride/fan control and connects to connector contacts 37 and 39. The purpose of the solenoid valve is to activate or deactivate the ride control function. When the control sends a +battery (approximate) signal to the solenoid, the ride control function is activated. When the control does not send a signal to the solenoid, the ride control function is deactivated.The ride control solenoid valve is part of the high ambient cooling control valve. The solenoid valve has a connector with two contacts. Solenoid connector contact 2 receives power from connector contact 37 of the ride/fan control. Solenoid connector contact 1 returns the power to connector contact 39 of the ride/fan control.Fan Solenoid Valve
Fan Solenoid ValveThe fan solenoid valve is an output of the ride/fan control and connects to connector contacts 38 and 39. The purpose of the solenoid valve is to activate or deactivate the