HARNESS AS-WIRING 2784898 - Caterpillar

Inputs
The machine has several different types of input devices. The ECM receives machine status information from the inputs devices and determines the correct output action that is needed in order to control machine operations based on memory and software parameters. the machine utilizes the following types of inputs: switch type and sensor type.Switches provide signals to the switch inputs of the ECM. The possible outputs of a switch are listed: an open signal, a ground signal and + battery signal.Sensors provide an electrical signal to the ECM that constantly changes. The sensor input to the ECM can be one of several different types of electrical signals such as: pulse width modulated (PWM) signals, voltage signals and frequency input signals. Each possible input to the ECM is listed in the tablesSwitches
Reversible Fan Switch
Illustration 2 g03832074The reversing fan can be enabled or disabled using Cat ET. By default this is enabled. If, you press the reversible fan switch the light will blink and the ECM will engage the reverse mode for the fan. If, the light is solid the fan is in Auto mode and the fan will reverse for a predetermined time on a set interval. These are also adjustable using Cat ET.Sensors
Hydraulic Oil Temperature
Illustration 3 g01113896The temperature sensor is a passive analog sensor. The signal voltage of the sensor corresponds to the temperature of the hydraulic oil. The voltage signal is an input to the Machine ECM. This voltage signal will vary representing changes in the hydraulic oil temperatures. The temperature of the sensor is displayed on the instrument cluster. The temperature is represented in either Metric units or English units. The temperature is accessible by scrolling through the display.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.Solenoids
Illustration 4 g02747758
Typical example of a solenoid valve
(1) Pin 1
(2) Pin 2 Demand Fan Proportional Solenoid Valve
The demand fan proportional solenoid valve is located on the bottom side of the fan motor housing. The demand fan proportional solenoid valve receives a variable PWM signal from the Engine ECM based on the machine temperature sensor inputs.Demand Fan Reversing Solenoid Valve
The demand fan reversing solenoid valve is located on the top side of the fan motor housing. The demand fan reversing solenoid can be operated manually or automatically. In manual mode, the operator chooses when to reverse the fan by pressing the reversing fan button on the keypad in the cab. In automatic mode the ECM will reverse the fan for 10 seconds every 30 minutes.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 control for the product link provides a global positioning system for the machine.The data link is bidirectional. The bidirectional link allows the ECM to input information