ENGINE AR-COMPLETE 1695166 - Caterpillar

Illustration 1 g06138882
Fan Electrical Schematic
(1) B+ from engine ECM fuse
(2) B+ from machine fuse
(3) Hydraulic oil temperature sensor
(4) ATAAC air temperature sensor
(5) Engine coolant temperature sensor
(6) Fan solenoid
(7) Engine ECMWhen the electrical disconnect switch is in the ON position, power transfers from engine ECM fuse (1) to engine ECM (7). This voltage provides the main power source for the engine ECM.When the start switch is in the ON position, power transfers from machine fuse (2) to terminal "J1-40" of engine ECM (7). This voltage provides the wake-up signal to the engine ECM.When engine ECM (7) is active, the ECM monitors the hydraulic oil temperature, the engine coolant temperature, and the ATAAC air temperature.Hydraulic oil temperature sensor (3) is a resistance type sensor. Engine ECM (7) passively monitors input from this sensor at terminal "J1-5". The hydraulic oil temperature sensor is grounded at terminal "J1-34" of the engine ECM. Software in the engine ECM converts the signal at terminal "J1-5" into a temperature value.Engine coolant temperature sensor (5) is a resistance type sensor. Engine ECM (7) passively monitors input from this sensor on connector"J2". Software in the engine ECM converts the signal into a temperature value. ATACC air temperature sensor (4) is a resistance type sensor. Engine ECM (7) passively monitors input from this sensor on connector"J2". Software in the engine ECM converts the signal into a temperature value.Note: Refer to the engine wiring diagram for information about input components to connector "J2".Engine ECM (7) evaluates the input signals from the above sensors to determine the output signal to send to fan solenoid (6). The engine ECM sends this signal from terminal "J1-29" to contact "1" of the fan solenoid. Contact "2" of the fan solenoid is grounded at terminal "J1-25" of the engine ECM. The greater the output signal, the slower the speed of the fan. The minimum and maximum solenoid currents are adjusted with the ET software.