Model 4700 Maintenance Manual
Section 8. Theory of Operation
All Dual Traction Motor Trucks and Single Traction Motor Trucks <S/N 10677 Item
Connection
Function Description
Theory of Operation
Normal Level
Pinout Matrix Signal Source
Signal User
129
J8-1
GND
Ground to Horn push button switch (PB4) from VM (J34-6). If not present, check VM, wiring, and connections.
Battery voltage wrt BT1+
VM
PB4
130
J8-2
HORN IN
Horn push button (PB4) input to VM (J34-16). If not present, check switch, wiring, and connections.
Approx. 5V open; 0V closed
PB4
VM
131
J8-3 and 4
NOT USED
132
J11–
HR 1 GND
B– to the Horn (HR1). If not present, check wiring and connections.
Battery voltage wrt BT1+
B–
Horn
133
J11 IN
HORN OUT
Control voltage to Horn (HR1) from the VM (J34-9). If not present, check VM, switch, wiring, and connections.
+24V normal goes to 0V when horn button depressed
VM
Horn
134
J11+
+24V
+24V to the Horn (HR1) from the DC/DC Converter. If not present, check fuse F6, wiring, and connections. Approx. 65 ohms across coil (J11+ to J11–).
+24V
DC/DC Converter
Horn
135
J13-1
+12V
+12V to the Pump Motor (PM) encoder (EN3). If not present, check the PPA, wiring, and connections.
+12V
PPA
EN3
136
J13-2
GND
Ground to the Pump Motor (PM) encoder (EN3). If not present, check the PPA, wiring, and connections.
Battery voltage wrt BT1+
PPA
EN3
137
J13-3
PM ENCODER CHANNEL A
Channel A from the Pump Motor (PM) encoder (EN3). If not present, check voltage to the encoder, wiring, and connections.
Approx. 5V running; 0V or 10V static
EN3
PPA
138
J13-4
PM ENCODER CHANNEL B
Channel B from the Pump Motor (PM) encoder (EN3). If not present, check voltage to the encoder, wiring, and connections.
Approx. 5V running; 0V or 10V static
EN3
PPA
139
J13-5
TERM
Dual Traction Motor Truck Ground from the PPA to the Pump Motor (PM) temperature switch (TS3). If not present, check the PPA, wiring, and connections.
Battery voltage wrt BT1+
PPA
TS3
140
J13-5
TERM
Single Traction Motor Truck Ground from the VM (J34-6) to the Pump Motor (PM) temperature switch (TS2). If not present, check the PPA, wiring, and connections.
Battery voltage wrt BT1+
PPA
TS2
Publication 1160093, Issued: 20 May 2013
8-23
