Lull 6K Service Manual - Manual (Page 522)

Frame Tilt and Oscillation
7-20 Service Manual — Models 644B, 6K, 844C, 8K, 1044C, 10K
Boom Positioned Above 40°
Fig. 7-13: Circuit Operation Above 40°
(Ref. Fig. 7-13) The following describes the rear axle stabilizer circuit logic
when the boom is positioned above 40° elevation.
1. When the boom is above 40°, the proximity switch (S1) is not sensing
the outer boom. Therefore, the proximity switch opens.
2. When the proximity switch is open, the proximity switch relay (R1) is
not energized and power is directed to the transmission Electronic
Control Unit (ECU). The ECU signals the transmission to drop
pressure to the forward and reverse clutches, placing the transmission
in a neutral position.
3. Since (R1) is not energized, no power is directed through the service
brake relay (R2) and on to the solenoid valve (V1) on the stabilizer
block. Therefore, the stabilizing cylinder assumes a locked position.
See “Oscillation Control Block” on page 7-31 for more information.
4. Also, there is no power directed from relay (R1) to the frame tilt lockout
solenoid valve (V2). Therefore, pilot pressure at the frame tilt control
valve spool is directed to the tank and there is no spool movement or
frame tilt function.
5. With relay (R1) not energized, no power is relayed to the rear
oscillation lock warning light relay (R3). Therefore, the indicator light on
the dash panel maintains a path to ground and the light in the
instrument cluster illuminates, indicating oscillation lock engagement.
J
1260
Dash Panel
ECU
R1 R2 R3
S2 S3
S1
V2
V1
B
1
C
Parking
Pressure
Brake
Switch
Fuse
Panel
Transmission
Disconnect
Switch
R1 = Proximity Switch Relay
R2 = Service Brake Relay
R3 = Oscillation Lock Warning Light Relay S1 = Proximity Switch
S2 = Service Brake Pressure Switch
S3 = Frame Tilt Override Pressure Switch
V1 = Stabilizer Block Solenoid Valve
V2 = Frame Tilt Lockout Solenoid Valve
B
A
C
B
A
2
3
6
5
4
A B C D E F
D
2 3 7
+
+ –
–
A
B
C
Solenoid
Valve On
Stabilizer
Block
B
A
6 Pole
W/P
Conn.