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ELECTRONIC CONTROL SYSTEM
PDC#
Device
F4
30A...IDM/ECM
F12
20A...RUN/ACC
F40
10A...IDM LOGIC
F46
5A...ECM KEY PWR
R
IDM RELAY - POSITION 55
2
STARTER
MOTOR
RELAY
IDM Relay Circuit Operation
• The IDM controls its own power up
and power down process. When
the key is OFF, the IDM stays
powered up for a brief period. The
IDM then powers down after
internal housekeeping functions
have been completed.
IDM Power Up
• The key switch receives battery
voltage from the Power Distribution
Center (PDC) F-12 fuse. When the
key is ON, the switch supplies
battery voltage through F-46 fuse
and pin 9 of the engine 12-way
connector to pin X3-7 of the IDM.
• Battery voltage is available through
the PDC F-4 fuse to IDM relay pin
30 and 85 at all times. Pin 85
supplies voltage to the relay coil.
Pin 86 takes that voltage through
pin 8 of the engine 12-way
connector to pin X3-27 of the IDM.
28
ECM
BATTERY
200 A
F4
F-46
KEY SWITCH
When the key is ON, voltage
supplied to pin X3-7 signals the
IDM to provide a ground circuit to
pin X3-27. When this occurs,
current flowing through the IDM
relay coil builds a magnetic field
that causes the relay to latch. When
latched, the relay connects pin 30
to pin 87 and supplies current
through pin 12 of the engine in-line
12-way connector to pin X3-4, X3-
23, X3-24, and X3-25 of the IDM.
Four pins receive voltage to spread
the current draw over multiple pins.
International
X3-8 IDM LOGIC POWER
X3-24 IDM MAIN POWER
X3-25 IDM MAIN POWER
X1
X1
X3-4 IDM MAIN POWER
X2
X2
X3-23 IDM MAIN POWER
X3
X3
X3-27 IDM MPR
X4
X4
X3-7 V
IGN
R
2
30
87
TO IDM RELAY
F40
85
86
F-12
• The IDM also requires voltage for
®
VT 275 V6 Engine
X1
X1
X2
X2
X3
X3
IDM
PDC
12
6
8
9
ENGINE IN-LINE
12-WAY
IDM Logic
the internal logic circuit. When the
IDM relay latches, pin 87 of the relay
supplies voltage to the IDM logic
circuit through the F-40 fuse in the
PDC. The F-40 fuse feeds through
pin 6 of the engine in-line 12-way
connector to the IDM pin X3-8.
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