JLG 19AMI Service Manual - Manual (Page 52)

SECTION 3 - TROUBLESHOOTING
3-6 – JLG Lift – 3121190
Table 3-1. 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.
Red emergency stop button is engaged (PUSHED IN) on
either ground control station or on platform. Disengage (TURN CLOCKWISE) red emergency button
until it pops out.
Floor Stop is not engaged. Engage Floor Stop at either side 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 Stop Limit Switch (caus-
ing 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.