ELECTRONIC SPEED CONTROL
Read all of SAFETY and this section before attempting any procedure. Pay particular attention to Notices, Cautions, Warnings and Dangers.
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Repair and Service Manual
634756
ELECTRONIC SPEED CONTROL
SPEED SENSOR
The speed sensor uses a sealed sensor to sense teeth of
gear attached to the motor’s armature shaft. Gear tooth
impulses are converted into electrical signal which the
controller uses to determine motor speed.
Fig. 1 Speed Sensor
CONTROLLER
The controller is a solid state unit that activates a sole-
noid and controls the function of the vehicle by respond-
ing to inputs from the throttle position sensor, motor
speed sensor and many other units. The controller is
located under the bed at the rear of the vehicle (Ref. Fig.
Fig. 2 Controller
The main wire harness, throttle position sensor, and
speed sensor are connected to the controller through a
35-pin plug. The throttle position sensor is connected to
the controller through a 4-pin plug on the main wire har-
ness. The speed sensor is connected to the controller
through a 4-pin plug on the main wire harness.
The controller is wired to the batteries and develops a
regulated power supply for the throttle position sensor.
As the pedal is pressed, the magnitude of deflection in
the throttle position sensor varies the voltage, which in
turn is fed back to the controller. The controller interprets
the change in voltage and supplies the appropriate
power to the motor.
The throttle position sensor unit and the controller are
both solid state units that contain no user serviceable
parts. The testing procedures are designed to test the
basic functionality of the power and control wiring sys-
tems. Once the functionality of the wiring has been con-
firmed, the remaining tests are used to identify which of
the components (controller or throttle position sensor)
must be replaced.
CONTROLLER REPLACEMENT
Tool List
Qty.
Socket, 7/16”................................................................1
Socket, 13/32”..............................................................1
Ratchet.........................................................................1
Extension, 6"................................................................1
Wrench, 7/16” ..............................................................1
Wrench, 13/32” ............................................................1
Insulated Wrench, 1/2”.................................................1
Torque Wrench, ft. lbs ..................................................1
To prevent electrical shock, the BL- wire must
be removed before discharging the controller
by shorting the B+ and B- terminals of the
controller with a large screwdriver. Be sure to
hold screwdriver by the insulated portion.
Note the location of the wiring before disconnecting
from controller.
Use an insulated wrench to remove the BL- wire from the
battery.
Speed Sensor
Controller
Front of Vehicle
