JLG 3248RS/10RS Service Manual - Manual (Page 83)

SECTION 4 - HYDRAULICS
3121273 – JLG Lift – 4-3
the Pump Motor Positive and Negative Terminals is
less than 2 Ohms. If not, examine the pump motor
for worn brushes or broken terminals. After examina-
tion, re-connect the Pump Motor Positive Terminal
and main power at the batteries.
4. Short-Circuit between Pump Motor Positive and
Negative Terminals
This issue will allow the vehicle to drive, but Lift Up
and Steer Functionality will be lost and the Pump
Motor will not operate. Under DIAGNOSTICS -
PUMP, the JLG Analyzer will show an erratic reading
for PUMP PWM % and PUMP CUR will hover around
150A when Lift Up is operated from Ground Mode.
Disconnect main power at the batteries to com-
pletely de-energize the Control System. Next,
detach both Pump Motor Terminals and insulate
them independently. Re-connect main power at the
batteries and re-try Lift Up. If the same symptoms
persist (erratic PUMP PWM%, PUMP CUR around
150A), examine the cabling between the Pump
Motor and Power Module compartment for a short-
circuit (most likely near area where cylinder retracts
between frame side sheets or near pot-hole mecha-
nism, if equipped). If the symptoms change, suspect
a short-circuited (or mechanically frozen) pump
motor.
A clamp-on ammeter (set for 200A DC) can be
placed on either Pump Motor Cable for verification.
During Lift Up, the ammeter will read approximately
150A.
Hydraulic Oil Check Procedure
Lube Point(s) - Hydraulic Reservoir
Lube - Hydraulic Oil
Interval - Check Daily
NOTE: Check the hydraulic oil level with the platform in the
stowed position ONLY. Be certain the hydraulic oil
has warmed to operating temperature before
checking the oil level in the reservoir.
1. On the left side of the machine, remove the side
access door on the base frame. Locate the
hydraulic oil reservoir (1) on the pump unit (2).
Check the oil level in the hydraulic reservoir by look-
ing at the markings on the side of the tank. The res-
ervoir is marked with a MAX (maximum) marking
(3). The oil level must be kept at or within one (1)
inch of this marking to operate properly.
2. If additional oil is required, wipe all dirt and debris
from the filler/breather cap (4) area, add proper
grade of oil. Fill until oil level is close to the MAX
marking (3), but not over the MAX marking.
NOTE: Care should be taken not to introduce any impurities
(dirt, water, etc.) while cap is removed.
-B
P
+B
Series DC
Pump Motor
24V
Line Contactor
Power Module
Table 4-1. Hydraulic System Capacities
COMPONENT 1932RS/6RS 3248RS/10RS
Hydraulic Tank 1.32 Gal. (5 L) 2.38 Gal. (9 L)
Hydraulic System 1.85 Gal. (7 L) 3.96 Gal. (15 L)