Lull 944E-42 Service Manual - Manual (Page 728)

Electrical System
9.218 Model 644E-42/944E-42 Rev. 6/04
9.14.5 Auxiliary Hydraulic Pressure
Release Switch
644E-42, SN 20118 & Before,
0160002519 thru 0160003108,
944E-42, SN 20123 & Before,
0160002514 thru 0160003106
The auxiliary hydraulic pressure release switch (1) is
located in the upper bank of switches on the right side of
the dash and is pressed or “snapped” into a rectangular
switch bezel.
The auxiliary hydraulic pressure release switch is a
momentary rocker switch. This switch is used to release
pressure in the auxiliary hydraulic system before
connecting or disconnecting the auxiliary hydraulic
couplers. The bottom (2) of the switch is pressed and held
for two seconds. When release the switch returns to the
OFF (3) position automatically.
The switch is marked with a symbol (4) on the lower
portion of the switch. When the auxiliary hydraulic
pressure release switch completes the auxiliary hydraulic
pressure release circuit. The auxiliary hydraulic pressure
release solenoid (5) on the auxiliary hydraulic pressure
release valve (6) is normally de-energized, allowing the
auxiliary hydraulic pressure release to engage. When the
auxiliary hydraulic pressure release solenoid is
energized, the auxiliary hydraulic pressure release valve
routes the pressurized oil back to tank.
a. Auxiliary Hydraulic Pressure
Release Switch Removal
1. Unlock and open the engine cover (7).
2. If the vehicle has dual batteries, disconnect both
negative battery cables (9 and 10) from both
batteries.
To access the lower battery (11), loosen the
knob (12) far enough so that the lip (13) on the upper
battery box clears the knob. Lift up the upper battery
box (14) and swing it out, so that the box clears the
hydraulic tank support bracket, to gain access to the
lower negative battery cable (9). Disconnect the
lower negative battery cable.
OU0501
1
OH2591
OH2611
2
3 4
B
A
MU5800
5
6
4110390
1.
2.
OU0780
8
8
7