26 SENR9977
Systems Operation Section
ECM Power Supply
g01141374
Illustration 32
Power Sup
ply for the ECM
The power supply to the ECM and the system
is drawn f
rom the 24 volt or the 12 volt battery.
The power supply for the ECM has the following
components:
•
Battery
•
disconn
ect switch
•
Key start switch
•
Fuses
•
Ground b
olt
•
ECM connector
•
Machine interface connector
Note: Th
e ground bolt is the only component that is
mounted on the engine.
The Sche
matic for the ECM shows the main
components for a typical power supply circuit. Battery
voltage is normally connected to the ECM. The input
from th
e key start switch turns on the ECM.
The wiring harness can be bypassed f or
troubl
eshooting purposes.
The display screen on the e lectronic service tool can
be used in
order to check the voltage supply.
Note: Twowiresareusedtoreduceresistance.
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