Unit Will Not Lower From Ground Control Toggle Switch; Platform Will Not Lower From Ground Control Toggle Switch - JLG 10VP Service And Maintenance Manual

Platform Will Not Lower From Ground Control Toggle Switch

Overview Of Procedure
The following procedure examines the complete ground control circuit from the battery all the way to the pump motor for
wiring or components which could be causing a failure of that circuit.
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 set to the Reset position)
• Ground control power supply and wiring, OK (Table 3-4).
• 5 amp fuses on power and pump circuits, OK.
• Hydraulic oil level, OK.
Table 3-25. Unit Will Not Lower From Ground Control Toggle Switch.
STEP
Will machine lower manually?
1.
2. Check for obstructions in the mast, cylinder, hydraulic lines and lift
down valve.
3. Check terminal 30 and 85 on the ground control relay for ground. Is
ground contact OK? Continuity with B–.
Check continuity across terminals 87 and 30 on the ground control
4.
relay. Is there continuity? (Relay must be energized)
5. Check the Black wire from terminal 87 on the ground control relay to
the lift up/down ground control switch. Is there continuity with B –?
Check for continuity across the terminals (Black to Tan, 4-1 wire) of
6.
the lift up/down ground control toggle switch. Is there continuity
with the switch activated?
Check the Tan, 4-1 wire for continuity from the lift up/down ground
7.
switch to the lift-down coil. Is there continuity?
Check the Yel/Red, 2-6 wire from the pump motor to the lift-down
8.
coil for voltage. Is there voltage?
3120728
ACTION
– JLG Lift –
SECTION 3 - TROUBLESHOOTING
SPEC YES
— Go to Step 3
Repair, Replace
—
or Adjust
Ground Go to Step 4
Ground Go to Step 5
— Go to Step 6
— Go to Step 7
— Go to Step 7
24 volts —
NO
Go to Step 2
Go to Step 3
Repair Wiring or
Connection
Replace Relay
Repair Wiring or
Connection
Replace Lift Up/
Down Ground
Control Switch
Repair Wiring or
Connection
Repair Wiring or
Connection
3-35