4-34 4262930-Rev A
ELECTRICAL
4
Troubleshooting
Symptom: Machine will not power up.
Symptom: Traction motor will not engage.
Probable Cause Remedy
Faulty battery pack. Test battery pack. (See “Battery Pack Test” on page 4-45.)
Faulty battery pack fuse. Test fuse. (See “Battery Pack Fuse Test” on page 4-50.)
Faulty generator. Test generator. (See “Gen-Set Output Test” on page 4-46.)
Faulty engine on/off switch Test engine on/off Switch. (See “Engine On/Off Switch” on page 4-47.)
Faulty 30A fuse. Test 30A fuse. (See “30A Fuse Test” on page 4-50.)
Faulty power circuit. Measure voltage between battery pack positive terminal and ground. Measure voltage
between main control unit connector J1-3 and ground. Voltage must be approximately
48 VDC.
Open ground circuit. Measure continuity between battery pack negative terminal and main control unit
connectors J2-26 and J2-33. Continuity must be indicated.
Faulty key switch. Test key switch. (See “Key Switch Test” on page 4-48.)
Faulty key switch power circuit. Measure voltage between key switch terminal B and ground. Voltage must be
approximately 48 VDC.
Faulty switch signal circuit. With key switch in start position, measure voltage between key switch terminal A and
ground. With key switch in the start position, measure voltage between main control
unit connector J2-24 and ground. Voltage must be approximately 48 VDC.
Faulty main control unit. Substitute main control unit with a known good main control unit.
Faulty main control unit power circuit. Measure voltage between main control unit connector J1-3 and ground. Voltage must be
approximately 48 VDC.
Open main control unit ground circuit. Measure continuity between battery pack negative terminal and main control unit
connectors J2-26 and J2-33. Continuity must be indicated.
Probable Cause Remedy
Faulty traction motor connections. Check connections (moisture, loose or corroded pins, etc.) and repair as necessary.
Faulty bail potentiometer. Test bail potentiometer. (See “Bail Potentiometer Test” on page 4-55.)
Faulty bail potentiometer power circuit. Measure voltage between main control unit connector J2-31 and ground. Measure
voltage between bail potentiometer terminal 1 and ground. Voltage must be
approximately 5 VDC.
Open bail potentiometer ground circuit. Measure continuity between main control unit connector J2-30 and bail potentiometer
terminal 1. Continuity must be indicated.
Faulty bail potentiometer input circuit. Measure voltage between main control unit connector J2-32 and ground. Measure
voltage between bail potentiometer terminal 2 and ground. Voltage must range
between 0 and 5 VDC.
Faulty throttle potentiometer. Test throttle potentiometer. (See “Throttle Potentiometer Test” on page 4-54.)
Faulty throttle potentiometer power circuit. Measure voltage between main control unit connector J2-15 and ground. Measure
voltage between throttle potentiometer terminal 3 and ground. Voltage must be
approximately 5 VDC.
Open throttle potentiometer ground circuit. Measure continuity between main control unit connector J2-29 and throttle potentiometer
terminal 1. Continuity must be indicated.
Faulty throttle potentiometer input circuit. Measure voltage between main control unit connector J2-16 and ground. Measure
voltage between throttle potentiometer terminal 2 and ground. Voltage must range
between 0 and 5 VDC.
Faulty traction motor. Test traction motor. (See “Traction Motor Test” on page 4-52.)
Faulty traction motor controller. Substitute traction motor controller with a known good controller.
Faulty main control unit. Substitute main control unit with a known good controller.
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