Service Manual

SECTION 6 - TROUBLESHOOTING
3121231 – JLG Lift – 6-39
6.12 MAIN POWER CIRCUIT TROUBLESHOOTING
Machine Will Not Power Up
Check For These Obvious Conditions First:
• Battery voltage is 24 volts. (Sufficient Charge in Batteries to Operate Machine)
• Positive (+) and negative (–) battery cable connections clean and tight at both the Batteries and the Ground Control Mod-
ule lugs.
• Main Power Selector Switch (key) positioned to either Platform or Ground Control Mode.
• Emergency stop buttons on both the Ground Control Module and the Platform Control Console in the RESET position
(out).
Table 6-43. Machine Will Not Power UP.
STEP ACTION SPEC YES NO
1. Check for 24V DC at the positive (+) and negative (–) main power cable
connections on the Ground Control Module.
24V DC Go to Step 2 Replace the 175
Amp Inline Fuse on
the Positive power
cable
2. Check continuity of the Emergency Stop wires running to the Platform Con-
trol Console, pins-10 and 1 on the P4 connector at the Ground Control Mod-
ule.
— Replace the Ground
Control Module
Go to Step 3
3. Remove the 9-pin Platform Control Console connector at the Platform
Junction Box and check continuity between pins-1 and 2 to the Emergency
Stop Switch in the Platform Control Console cable.
— Go to Step 4 Replace the
Platform Control
Console
4. Check continuity of the wires running from the P4 connector on Ground
Control Module to the Platform Junction Box;
P4 connector, Pin-1 to Junction Box Pin-2 and
P4 connector, Pin-10 to Junction Box Pin-1
— Replace Platform
Control Console
Repair or Replace
Wiring