Model 8210/8250 Maintenance Manual Section 5. Troubleshooting
Electrical Troubleshooting Guidelines
Publication:1146945/001, Revised: 25 Sep 2018 5-5
Section 5. Troubleshooting
Electrical
Troubleshooting
Guidelines
General
Block the lift truck so that the drive tire
is off the floor whenever a
troubleshooting procedure requires
turning the truck ON. This prevents
accidents caused by unexpected lift
truck travel.
Use extreme care when the truck is
jacked up for any reason. Keep hands
and feet clear while jacking the lift
truck. After the lift truck is jacked, place
solid blocks or jack stands beneath it to
support it. Do not rely on the jack alone.
See “Jacking Safety” on page 2-10.
Unless otherwise directed, disconnect
the battery connector when you check
electrical circuits or components with an
ohmmeter. Electrical current can cause
damage to the ohmmeter.
Many problems are caused by a faulty or dirty
battery. Make sure the battery is clean. Check
the electrolyte level and state-of-charge. See
“Lead Acid Battery” on page 7-40.
Save time and trouble by looking for simple
causes first.
Visually inspect all wiring and electrical
components for:
• Loose connections or connectors
• Loose or broken terminals
• Damaged terminals, blocks, or strips
• Broken wiring and shorted conditions
(especially those that are close to metal
edges or surfaces)
Use an ohmmeter to check for wiring continuity
and shorts.
Use a Digital MultiMeter (DMM), such as a
Fluke meter, for all measurements. Analog
meters can give inaccurate readings and load
down sensitive electronic circuits enough to
cause failure. Make sure meter cables are
connected to the correct meter jacks and that
the correct function and scale are selected.
When measuring voltage, connect the positive
meter lead to the connector or probe point
marked (+) in the test. Connect the negative
meter lead to the connector or probe point
marked (–).
Whenever measuring resistance, turn the truck
OFF and disconnect the battery connector.
Battery current can damage an ohmmeter.
Isolate the component from the circuit.
For troubleshooting DC electric motors, see “DC
Electric Motors” on page 5-8.
For troubleshooting AC electric motors, see “AC
Electric Motors” on page 5-14.
For information on pin, connector, and harness
connections, see “Wiring Harness” on
page 7-68.
Shorts to Frame
Shorts to frame is an industry term for
unintentional current leakage paths between
normally isolated electrical circuits and their
metal enclosures.
Shorts to frame may be metallic connections,
such as a wire conductor contacting metal
through worn insulation. More often, shorts to
frame are resistive “leakage” paths caused by
contamination and/or moisture.
These leakage paths can result in unwanted
electrical noise on the metallic pallet truck
structure and can cause incorrect operation.
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