Unit Will Not Power Up From Ground Control; Unit Will Not Power Up From Ground Control; Main Power Circuit Troubleshooting - JLG 10VP Service And Maintenance Manual

3.7 MAIN POWER CIRCUIT TROUBLESHOOTING

Unit Will Not Power Up From Ground Control

Overview Of Procedure
The following procedure tests the circuits from the Battery (+) terminal through the Ground Control Box and to the Main
Contactor Relay and Main Contactor for 24 volts or more. Also the Lift Up/Down Relay circuit is tested.
Check For These Obvious Conditions First:
• Battery voltage 24 volts. (Fully charge batteries)
• Battery connections clean and tight.
• Key switch positioned to Ground (GRND) control.
• Emergency stop switch pulled out. (Reset Position)
STEP
Check the 5 amp inline fuse on the Red 1-1 wire from the battery (+)
1.
terminal to the ground control box, key switch.
(Under pump/motor cover).
Ground Control Box Assembly (Disassembled)
Is there 24 volts or more reading at the key switch, terminal B.
2.
Check for 24 volts or more on the Yel/Red, 2-7 wire from the key
3.
switch to the E-stop switch.
Check for 24 volts or more on the Yel/Red, 2-8 wire from the E-stop
4.
to the Ground Control Relay, terminal 86.
Check for 24 volts or more on the Yel/Red, 2-4 wire from the E-stop
5.
to the Main Contactor Relay, terminal 87.
Main Contactor Circuit
6. Check for 24 volts or more on the Yel/Red, 2-4 wire from the Main
Contactor Relay, terminal 87 to the Main Contactor.
7. Did Main Contactor close?
Is the Black ground wire connection from the Main Contactor to
8.
ground OK?
9. At this point, 24 volts should be present at the following terminal
points; • Terminal 86 on the Ground Control Relay.
• Main Contactor, Yel/Red, 2-4 wire.
With Main Contactor engaged, 24 volts or more should be present at
10.
the following terminal points;
• Pump Motor - 21' cable #1.
• Yel/Red, 2-6 wire on the Pump Contactor.
• Yel/Red, 2-6 wires on the Lift Up/Down Relay.
3120728
Table 3-4. Unit will not Power Up From Ground Control.
ACTION
SECTION 3 - TROUBLESHOOTING
SPEC
24 volts
24 volts
24 volts
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– JLG Lift –
YES NO
OK, go to Step 2 Replace Fuse
Check Wiring
from Battery to
Go to Step 3
Terminal B.
Repair or Replace
Repair wiring or
Go to Step 4 Replace Key
Switch
Repair wiring or
Go to Step 5 Replace E-Stop
Switch
Repair wiring or
Go to Step 6 Replace E-Stop
Switch
Repair wiring or
Go to Step 7 Replace Main
Contactor Relay
Go to Step 9 Go to Step 8
Replace Main Repair Ground
Contactor Wiring
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