72V Common
• The 72V common is referred to as -72V in the schematics.
• In the SD you can remove the center traction battery cover and connect to the negative
terminal of the battery closest to the dash.
• In either the SD or the PK you can remove the center dashboard switch plate (two screws)
and connect to the black wire of the heater switch.
• When in the rear of the vehicle, use the B- post on the motor controller A21.
• When using a voltmeter, set to an appropriate scale for 72V (usually the 200V range).
• Use your red voltmeter wire to probe the 72V electrical system.
Common Electrical Problems
The most common problems include loose wire connections and fuse and connector problems. Since
the Xebra is a simple vehicle, the solution is often simple. It is important to be just like a doctor and
be a good detective.
WARNING and Safety !
• Both electrical systems are capable of very high currents (means blinding light, sparks,
fire and welding are possible).
• The 72V system is also capable of giving you a serious voltage shock.
• When working on the vehicle, all tools and handles should be wrapped in electrical tape
or rubber coated to avoid shorting terminals; that is, never touch the positive to a
negative of any part of the system or any battery.
• Positive and negative locations may not be immediately obvious, especially on the
motor controller and the printed circuit card.
• Take all standard precautions for electrical systems including removing rings and
watches, wear safety glasses and gloves and proceed cautiously using common sense.
• Unless necessary for troubleshooting, make sure the 12V cutoff switch and the 72V
cutoff switch are off. They must always be off whenever you are changing components
(such as the motor controller), fuses or wiring.
Check for Tight Wiring Connections
• wires on fuse and diode blocks
• wires to and between batteries
• wires to main traction battery fusible link F9
• wires to contactors
• wires to motor controller
• wires to drive (traction) motor
• Make sure the small wires on the motor controller (A21) are tight; crimp as necessary
Fuse problems, solutions and tips
• The PK uses standard blade fuses and do not have the following problems.
• The SDs originally used wire wound fuses. These fuses can discolor (oxidize) over time
(which causes the resistance to increase). Refer to the waterproofing and reliability guide for
information on replacing these fuses.
• If you find such fuses they must be removed and changed to standard
automotive blade fuses.
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