JLG sky trak mmv Service Manual page 535

Before troubleshooting any
electrical circuit, ALWAYS
begin by checking the
following:
1. All connections relating
to circuit are clean and
tight
Model MMV Rev. 12/04
Boom fails to extend
or retract.
Check that L.E.D. on
logic panel is illuminated
with key ON.
If OK
Check for battery voltage on
circuit 37 (yellow tie wrap)
at extend solenoid on
pilot select manifold at
rear of unit.
If OK
Check solenoid for proper
resistance (7-10 ohms).
Replace solenoid if open or
short to ground.
If OK
Refer to Section 9, Hydraulic
System for cartridge removal,
inspection and installation
procedures.
Electrical System
Check 7.5 amp
Not
OK logic panel fuse.
Check circuit 37 for open
Not
OK or short to ground.
If OK
Check circuit 43 (GRY/BRN)
for battery voltage
to logic panel.
If OK
Replace logic panel.
10.55