SECTION 3 - TROUBLESHOOTING
3120743
– JLG Lift –
3-15
Table 3-6.Electrical System - Troubleshooting
TROUBLESHOOTING CHART
TROUBLE
PROBABLE CAUSE
REMEDY
ELECTRICAL SYSTEM.
Controller.
No electric power to controller.
Check electrical input to controller.
Steer valve will not function when thumb switch is moved in either direction.
No electric power to valve.
Check electrical output and electrical signal at the
valve.
Improper grounding.
Check for proper ground.
No response to a function control switch.
EMERGENCY STOP switch not position prop-
erly.
Place EMERGENCY STOP switch to the ON
position.
PLATFOR/GROUND SELECT switch not posi-
tioned properly.
Place PLATFOR/GROUND SELECT switch to
correct position.
Batteries defective or require charging.
Test batteries for serviceability. Replace or
charge batteries as necessary.
No voltage supplied to drive motors.
Check motor controller and contactors for proper
operation. Repair or replace as necessary.
Defective function switch.
Replace switch.
Defective circuit breaker.
Replace circuit breaker.
No voltage present at applicable control valve.
Check applicable wire for proper connection.
Using suitable test meter, perform continuity test
on wire. Repair or replace wire as necessary.
Defective motor/pump assembly.
Replace motor/pump assembly.
Drive motors will not operate when controller is activated.
Motor controller 200 Amp fuse blown.
Check flashcode on sevcon and determine cause
and repair. Replace fuse.
Hydraulic motor/pump will not run.
Batteries require charging or will not charge.
Charge or replace batteries as necessary.
Motor controller contactors not functioning prop-
erly.
Repair or replace contactor.
Motor/pump not functioning properly.
Repair or replace motor/pump.
Motor controller malfunctioning.
See REMEDY column.
Refer to Section 8 for malfunction codes.
Property of American Airlines