Taylor-Dunn B0-T48-48 Taylor Truck T48 Operation Manual page 106

Electrical Troubleshooting
Test 1. CHECKING THE CONTROL LOGIC INPUTS
Close the seat switch. Place the high/low switch in the HIGH position.
Connect a voltmeter across the ISO solenoid coil terminals and carefully monitor the voltage as
the key switch is turned on.
Turn the key switch ON and wait 1-second until the Isolator contactor closes.
Perform the following tests:
TEST 1.1
The coil voltage should start at approximately 24 volts when the key is turned ON, then drop to
approximately 15 volts after about 0.5 seconds.
If the test is good, then skip ahead to test # 1.2.
If the voltage starts high, drops to 15 volts, and then drops to 0 volts, then it indicates an
open circuit to the main battery positive. Check the continuity of the ISO solenoid contacts,
the main circuit breaker, and the wiring to the main battery positive post.
If the voltage is starts at 24 volts but the solenoid does not pick up, then skip ahead to
section #5.
If the voltage does not start at 24 volts, then go to section #4.
TEST 1.2:
Test the voltage from B+ to B- on the Controller.
If the voltage equals battery volts, then go to test
#1.3.
If the voltage does not equal battery volts, then:
•
Check the main positive wire to the circuit breaker
for open circuits.
•
Check the wire from the circuit breaker to battery
positive.
•
Check the wire from the contactor to B+ on the
controller for open circuits.
•
Check the wire from B- to battery negative on
the controller for open circuits.
Stop trouble shooting here and repair the problem. When the repair is completed, completely
retest the vehicle before lowering the drive wheels to the ground.
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.
After any repairs are made, completely retest the vehicle before
lowering the drive wheels to the ground. Failure to retest the vehicle
could result in unexpected movement of the vehicle resulting in injury
or property damage.
Section 4 Page 4