JLG G12-55A Service Manual - Manual (Page 155)

9-13 G10-55A, G12-55A
Electrical System
9.6.2 Charging Circuit
Before using a battery charger, an attempt can be made
to recharge the battery by jump-starting the machine
(Refer to the appropriate Operation & Safety Manual).
Allow the engine to run, which will enable the
alternator (2) to charge the battery.
If the engine alternator charging warning indicator
illuminates, perform the following checks:
1. Check all batteries cable connections at the battery,
and verify that they are clean and tight.
2. Check the in-line fuse below radiator.
3. Check external alternator wiring and connections,
and verify that they are in good condition.
4. Check the fan belt condition and tension.
5. Run engine and check alternator for noise. A loose
drive pulley, loose mounting hardware, worn or dirty
internal alternator bearings, a defective stator or
defective diodes can cause noise. Replace a worn or
defective alternator.
9.6.3 Alternator
a. Alternator Removal
1. Park machine on a firm, level surface, level machine,
fully retract boom, lower boom, place transmission
control lever in (N) NEUTRAL, engage park brake
and shut engine OFF.
1. Place a Do Not Operate Tag on both ignition key
switch and steering wheel.
2. Open engine cover. Allow system fluids to cool.
3. Properly disconnect the batteries.
4. Install a drive ratchet into the square hole in the
serpentine belt tensioner bracket (3).
5. While lifting the automatic belt tensioner away from
the belt, remove the fan serpentine belt.
Note: Record how the alternator is installed to ensure
correct installation later.
6. Label and disconnect the wire leads attached to the
alternator assembly.
7. Remove the lower mounting capscrew securing the
alternator to the lower mounting hole on the engine.
8. While supporting alternator with one hand, remove
upper (longer) mounting hardware from upper
alternator mount. Remove alternator from machine.
b. Alternator Installation
1. Position alternator and align with upper alternator
mount on engine bracket. Insert upper (longer)
mounting hardware through alternator mount.
Thread longer capscrew into alternator front mount.
DO NOT tighten completely at this time.
2. Align lower alternator mount hole with lower
mounting bracket on engine, and insert lower
mounting capscrew. Tighten lower capscrew and
upper capscrew securely.
3. Place a drive ratchet into square hole on serpentine
belt tensioner bracket (3). Apply pressure against
tensioner bracket and route serpentine belt onto
alternator and engine pulleys. Release and check
tensioner pulley to verify that it is pivoting freely in
order to provide proper tension on belt. Check for
proper belt alignment. (Refer to the appropriate
Operation & Safety Manual.)
4. Connect previously labeled wire leads to alternator.
5. Properly connect batteries.
6. Close and secure engine cover.
7. Remove the Do Not Operate Tags from both ignition
key switch and steering wheel.
MY7310
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