PLUG 4N8478 - Caterpillar

Inputs
The inputs describe the status of the machine systems. The inputs in this case are a switch type. Switches provide an open, a ground, or a + battery signal to the inputs of the controller. The inputs to ECMs are listed in table .Switches
Switches provide one of the following types of inputs to the ECM:
Open
Ground
+BatterySwitches are devices that have two states, opened or closed.
When a switch is open, no signal is provided to the corresponding input of the ECM. This condition is also referred to as floating.
When a switch is closed, a ground signal or a +battery signal is provided to the ECM. Steering/Brake Pump Case Drain Switch / Steering Cooling Oil Filter Bypass Switch
Illustration 2 g03662829The Steering/Brake Pump Case Drain Switch / Steering Cooling Oil Filter Bypass Switch is a pressure switch. The switch alerts the ECM when the filter is being bypassed. The contact floats to a high voltage when the switch is not closed. When the switch closes, the contact is pulled to a low or ground voltage state by the return line.Steering Pilot Filter Bypass Switch
Illustration 3 g03662875The steering pilot oil filter bypass switch is a pressure switch that shows whether the filter is plugged and the filter is being bypassed. The steering pilot oil filter bypass switch is a normally closed switch. The bypass switch will close at a given differential pressure notifying the ECM that the filter is plugged. The hydraulic filter bypass switch provides a ground to the ECM when activated.This switch is one of the inputs that is used in order to drive the "system indicator" in the instrument cluster.Primary Steering Pressure Switch
Illustration 4 g03662838The primary steering pressure switch is a pressure switch that is used to determine if there is sufficient pressure in the primary steering system. This switch has two outputs, one that is normally open and one that is normally closed. When the pressure in the primary steering system drops below the threshold, the outputs become closed and open respectively. Steering Tank Oil Low Level Switch / Steering Tank Oil Full Level Switch
Illustration 5 g03662833The steering tank oil level full and low sensor are switch to ground inputs to the implement ECM. These two components are sensors that function as switches. The steering tank oil level full/low sensors are used to monitor the steering tank oil level. Steering and Transmission Lock
Illustration 6 g03375229The switch tells the ECM when the operator has the lock lever in the locked position.
Table 4
Switch Status
Switch Position Normally Open Normally Closed
Locked Closed Open
Unlocked Open Closed Outputs
The ECMs respond 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. The outputs of the ECM are listed in tables .Data Link
Cat Data Link
The Cat Data Link is an input/output of the ECM. The data link uses the connector for the service port in order to communicate with the Caterpillar Electronic Technician. A data link connection is provided for the product link.Note: The