Taylor-Dunn B0-248-TT, Operation, T Roubleshooting And Replacement Parts Manual, Page: 115 / 204

Maintenance, Service, and Repair
Electrical Troubleshooting
Page 5
1. Make sure the start switch is in the “OFF” position, then remove the key.
2. Place the forward-reverse switch in the center “OFF” position.
3. Set the park brake.
4. Place blocks under the front wheels to prevent vehicle movement.
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 severe bodily injury and/or property damage.
Rotating rear drive wheels are a potential hazard. Keep hands, arms,
legs and loose clothing away from the rear drive wheels while
conducting tests. Failure to do so may cause serious bodily injury.
Preliminary System Tests:
Controller Battery Supply:
Connect voltmeter to the controller B+ and B- terminals.
Close the seat interlock switch, turn the key switch ON.
> Should be full battery voltage.
If correct go to Controller Output.
If test failed go to Contactors: ISO Contactor test.
Controller Output:
Connect the test light to the controller M- and controller B+ terminals.
Connect a volt meter to the controller M- and controller B- terminals.
Close the seat interlock switch, turn the key switch ON, select a direction and fully depress the throttle
pedal.
> The test light should start dim and then to full intensity with pedal fully depressed.
> The volt meter should start at full battery volts and then to less than 0.1 volts with
pedal fully depressed.
Light is ON and Volts < 0.1: The control system is working, perform tests in Motor Windings
and Contactors.
Light is ON and Volts > 0.1: The control system is not providing full power to the motor,
perform tests in Controller Small Signal Input for Pin #2. If good then replace the
controller.
Light is OFF: Continue with the following procedures.
These test procedures must be
performed in the order they were
written. If the test result is good,
then proceed to the next test or go
to the next section. Failure to do so
may result in incorrect test results.