Section 5. Troubleshooting Model 8210/8250 Maintenance Manual
Electrical Troubleshooting Guidelines
5-6 Publication: 1146945/001, Revised: 25 Sep 2018
Shorts to frame are caused by:
•Accumulation of dirt
• Battery electrolyte leakage
• Motor brush dust
• Motor brush leads touching the housing
• Breakdown in insulation
•Bare wires
• Pinched wiring harness
• Incorrect mounting of circuit cards
Shorts to frame can occur at numerous
locations on a pallet truck, including:
• Batteries
• Motors
• Cables, wiring, and harnesses
•Heatsinks
•Bus bars
• Solenoids
• Contactors
• Terminal strips
•Switches
• Power panel insulation
• Circuit card mounts
Shorts to Frame Test
To test for shorts to frame:
1. Turn the Main ON/OFF switch OFF and
disconnect the battery connector.
2. To test the battery for shorts to case,
connect a 12V test light to the battery case
from battery B+, and then to the battery
case from battery B–. If the light
illuminates at all, even momentarily, there
is a serious problem with the battery,
either external contamination or internal
damage. Do not continue until this
condition is corrected. The meter may be
damaged if you proceed before correcting
this condition.
a. Install another battery in the truck and
repeat this procedure from Step 1.
b. If the test light does not light, continue
to the next step.
3. Use a DMM set on the ampere function to
measure the current leakage from the
battery case to battery B+ and from the
battery case to battery B– (not truck B+
and B–). Begin measuring at the highest
ampere scale and work toward the lowest.
A reading of more than 0.001A (1mA)
indicates a serious short. Do not continue
until this condition is corrected. The meter
may be damaged if you proceed before
correcting this condition.
a. Install another battery in the pallet
truck and repeat this procedure from
Step 1.
b. If the current is less than 0.0002A
(0.2mA), go to Step 4. If the current is
greater than 0.0002A (0.2mA) and less
than 0.001A (1mA), remove the battery
from the truck, then continue with Step
4. Make sure the battery case does not
touch the truck frame during the
remaining tests.
4. With the battery disconnected (or removed
and disconnected) from the truck, use a
DMM to measure the resistance from
truck frame to truck B+, to truck B– (not
battery B+ and B–), and to all fuses and
motors. A reading of less than 1000 ohms
indicates a serious short. Do not continue
until this condition is corrected. The meter
may be damaged if you proceed before
correcting this condition. To correct the
condition, follow steps a through e.
a. To identify the cause of the short to
frame, disconnect circuit components
until the low resistance condition
disappears. Do not reconnect
components one at a time, but leave
them disconnected until the low
resistance reading disappears. Prevent
disconnected terminals or connectors
from touching the truck frame or other
conductive surfaces.
b. The most likely areas to check are:
•Motors
•Heatsinks
• Power cables
• Power circuit components
• Control circuit components
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