Test Equipment Required; Important Notes And Instructions; Definitions; Terminology Used - Taylor-Dunn B0-254-48 Operation, T Roubleshooting And Replacement Parts Manual

Electrical Troubleshooting

Test Equipment Required:

• Digital multimeter (DMM) with diode test
function, FLUKE 79 model shown.
• Throttle Module Analyzer, Taylor-Dunn part
number 62-027-32

Definitions:

• Battery volts = full voltage available at the
batteries at the time of test.
• High: Greater than +4.5 volts
• Low: Less than +1.8 volts

Terminology used:

• The "HOT" side of a switch is the terminal
that the power is connected to.
• The "COLD" side of a switch is the terminal
that the power is switched to.
• FS-1 = Micro-switch in the accelerator
module.
DURING ALL TESTS
• After any repairs are made, completely retest
vehicle before lowering the drive wheels to
the ground.
Turn the Key switch OFF BEFORE disconnecting
the batteries. Disconnecting the batteries with
the key switch ON may corrupt the controller
programming resulting in a fault code 1 (refer
to fault table).
Turn the Key switch OFF then disconnect both
of the battery leads during any maintenance or
before disconnecting any electrical component
or wire. Failure to do so may cause severe bodily
injury and/or property damage.
The rear drive wheels may rotate during some
of the following tests. Block the front wheels,
raise the rear drive wheels off the ground, and
support the vehicle with jack stands. Failure to
do so may cause the vehicle to move and cause
property damage and/or serious bodily injury.
Sevcon Troubleshooting
Page 2

Important Notes and Instructions

• This troubleshooting procedure is for the
Sevcon Power Pak and Micro Pak motor
speed controllers as equipped in standard
vehicles. Troubleshooting may not be valid
for vehicles equipped with special order
speed control options.
• For additional troubleshooting information,
use the handheld system anylizer part
number 62-027-61 or the computer system
anylizer (PCpaK) part number 62-027-63.
See note below.
• This troubleshooting guide assumes a
familiarity with the use of a digital multimeter
including, voltage tests, continuity tests, and
diode testing. If you are not familiar with
these types of tests then refer testing to a
qualified technician.
• These tests are not intended to locate a
problem on an incorrectly wired vehicle.
• Make sure the batteries are in good condition
and fully charged before performing any
tests.
• If the vehicle exhibits intermittent problems,
it must be in the failed mode for
troubleshooting. If it is running normally
when the testing is done then the problem
will not be identified.
• Some tests refer to a High/Low switch. The
High/Low switch is optional and the vehicle
may not be equipped with this option. If the
vehicle is without this option, there is a
jumper bypass installed in place of the switch
in the dash.
• All voltage tests are done referenced to
battery negative, unless otherwise specified.
• At the start of each test sequence you will
be instructed on how to place the control
switches. While testing, do not change the
position of any switches unless instructed
to do so.
Note: The PCpaK application is also capable of uploading
new controller parameters to the controller.
Controller parameter sets are available from Taylor-
Dunn. Individual parameters cannot be changed.
This troubleshooting guide is written in
sequential order. All tests must be performed in
the order that they are written. Starting in the
middle or skipping sections when not instructed
to do so may lead to invalid test results.