JLG 25RTS Service & Maintenance page 74

SECTION 3 - TROUBLESHOOTING
TROUBLE
Engine will not crank
Ammeter inoperative
Travel warning horn inoperative
Hourmeter inoperative
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Table 3-5. Electrical System Troubleshooting
PROBABLE CAUSE
Defective Platform/Ground select switch
No voltage present at function control switch
Defective function control switch
No voltage present at applicable control valve coil Check applicable wire for proper connection at
No voltage supplied to motor from start relay
Defective motor/pump assembly
ENGINE STARTER SYSTEM
Discharged battery or loose battery terminals
Starter relay faulty or faulty relay connections
Malfunctioning starter solenoid or motor
Defective start lockout solenoid
Malfunctioning ignition switch
Faulty ignition and/or starter circuit wiring
Defective ring gear or flywheel
INSTRUMENTS AND INDICATORS
Damaged wiring in circuits
Ammeter not functioning properly
Alternator not charging
Circuit breaker open
Damaged wiring in horn circuit
Damaged wiring in hourmeter circuit
Inoperative hourmeter
– JLG Sizzor –
REMEDY
Replace Platform/Ground select switch
Check wiring from power switch to function control
switch for proper connection or damage. Repair or
replace wiring as necessary
Replace function control switch
terminal strip, valve harness plug pin, valve har-
ness receptacle pin and valve coil. Using suitable
test meter, perform continuity test on wire. Repair
or replace harness as necessary
Check battery cable from relay to motor for proper
connection or damage. Repair or replace cable as
necessary
Replace motor/pump assembly
Check and charge battery or replace battery as
necessary. Clean and secure battery terminals
Using a test meter, check relay coil terminals for
presence of electrical power and for energization
of relay coil. Also check relay terminals for correct
switching of contacts. Replace relay as necessary
Replace solenoid or motor in accordance with
applicable manufacturer's manual
Replace start lockout solenoid
Using a test meter, check ignition switch for cor-
rect switching of contacts. replace switch as nec-
essary
Check wiring continuity. refer to wiring diagram
Replace ring gear
Repair or replace wiring
Replace ammeter
Repair or replace alternator
Determine and correct cause
Replace horn
Repair or replace wiring
Replace hourmeter
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