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
Pinout Matrix Signal Source
Signal User
Theory of Operation
Normal Level
Input from the Reverse Pedal switch (SW5) to the VM (J34-18). If not present, check switch, wiring, and connections. (Dual Pedal System)
Approx. 0V pedal released; approx. 5V pedal depressed
SW5
VM
192
J33-9
/BW
193
J33-10 thru12
NOT USED
194
J34-1
TAIL LIGHT
Output from VM to the Tail Lights (LP2 and LP4). If not present, check VM, wiring, and connections.
+24V
VM
LP2, LP4
195
J34-2
N POT
Negative reference for the Travel pot (P2). If this reference is lost or intermittent, the travel pot will not function correctly and possibly will throw codes. If not present, check VM, wiring, and connections.
Battery voltage wrt BT1+
VM
P2
196
J34-3
C POT
Wiper input from the Travel pot (P2). Voltage will vary depending on travel request. The pot may need to be re-learned. If not present, check pot, wiring, and connections. Note: To check pot, unplug connector and measure resistance between pins 2 and 3. Approx. 4.6K ohms should be read (J34-2 to J34-3).
Approx. 2V difference between neutral and pedal depressed
P2
VM
197
J34-4
NOT USED
198
J34-5
VCC
Voltage to Travel pot (P2). If not present check VM, wiring, and connections.
Approx. 10V wrt J34-2
VM
P2
199
J34-6
GND
One of the grounds supplied by the VM to multiple components. If ground is not present at this connection check for B– coming into the VM at (J34-7, 8, 10) and (J40-17).
Battery voltage wrt BT1+
VM
SW3 thru 10, 16, 30, PB2, PB3, PB4, PB9, TS1, TS2
200
J34-7
GND
B– supply to the VM. This B– is shared by many components prior to and after the VM. If not present, follow back towards B– until loss can be determined.
Battery voltage wrt BT1+
B– at J1–
VM
201
J34-8
GND
B– supply to the VM. This B– is shared by many components prior to and after the VM. If not present, follow back towards B– until loss can be determined.
Battery voltage wrt BT1+
B– at J1–
VM
Publication 1160093, Issued: 20 May 2013
8-29
