JLG 19AMI (3120758) Service Manual - Manual (Page 55)

SECTION 3 - TROUBLESHOOTING
3120758 – JLG Lift – 3-7
Table 3-2. DC Unit - Troubleshooting
TROUBLE PROBABLE CAUSE REMEDY
PLATFORM DOES NOT RISE.
Power source is OFF or unplugged. Check power source or Ground Station Key
Switch is switched to the ON position.
Red emergency stop button is engaged
(PUSHED IN) on either ground control station
or on platform. Disengage (TURN CLOCKWISE) red emer-
gency button until it pops out.
Foot Brake is not engaged. Engage Foot Brake at front of machine.
Control relay not functioning. Replace control relay.
Motor start relay not functioning. Replace motor start relay.
Fuse(s) blown. Replace blown fuse. If fuse blows again
check electrical circuit for short circuit.
Unit wiring not properly grounded. Check all grounds in the wiring.
Check for loose wire(s) on Floor Brake Limit
Switch (causing an open circuit). Properly reinstall wire to limit switch.
PLATFORM LOWERS BY ITSELF.
Manual descent valve open. Close manual descent valve.
Hydraulic hose and/or fittings loose causing
a hydraulic pressure leak. Tighten hydraulic hose and/or fittings.
Lift DOWN solenoid valve not functioning. Replace Lift DOWN solenoid valve.
UNIT LEAKING HYDRAULIC OIL.
Hydraulic hose and/or fittings loose. Tighten hydraulic hose and/or fittings.
Valve and/or plug loose. Tighten valve and/or plug.
Breather cap on tank is saturated or clogged
with oil. Replace breather cap on tank.
Hydraulic oil tank over-filled. Lower oil level to full mark on dipstick.
UNIT LOWERS VERY SLOWLY.
Flow control valve not functioning. Replace flow control valve.