MI91.327W
01NOV11
PART 11. EXCESS SLOPE
AUTOMATIC LEVELING SEQUENCE
725 TROUBLE SHOOTING STEPS
EXCESS SLOPE HAPPENS DURING THE AUTOMATIC LEVELING MODE WHEN TWO JACKS REACH FULL EXTENSION
AND ONE OR MORE YELLOW LEVEL LIGHTS REMAIN ON. WHEN THIS HAPPENS, THE 3000# PRESSURE SWITCH ON
THE MANIFOLD CLOSES SENDING A GROUND SIGNAL TO THE I/O MODULE. THE PUMP WILL SHUT OFF, THE SYSTEM
WILL NOT STABILIZE AND THE TOUCH PANEL WILL TURN OFF WITH THE "EXCESS SLOPE" LIGHT REMAINING ON
UNTIL THE JACKS ARE COMPLETELY RETRACTED WITH THE "STORE" BUTTON OR THE PARK BRAKE IS RELEASED.
Note: The leveling system manifold has a 50 psi pressure switch and a 3000 psi pressure switch.
Be careful to not interchange the 3000 psi switch with the 50 psi switch.
IMPORTANT: DO NOT LET THE PUMP RUN FOR MORE THAN SEVERAL MINUTES AT A TIME WHEN
PERFORMING EXCESS SLOPE TESTS. ALLOW THE PUMP MOTOR TO COOL IF THE MOTOR STARTS
TO BECOME HOT.
A. TWO JACKS ARE FULLY EXTENDED WITH A YELLOW LEVEL LIGHT STILL ON. THE PUMP
CONTINUES TO RUN AND THE SYSTEM WILL NOT SHOW "EXCESS SLOPE". The 3000 psi
manifold pressure switch is bad, the 8100 pressure switch wire is bad, the pump is not developing
enough pressure or the I/O module is the problem. In some cases, the shuttle valve may be the
problem. Unplug the 3000 psi manifold pressure switch. Use a small jumper wire to ground the pin for
the 8100 wire in the harness plug. Retry automatic leveling. The "EXCESS SLOPE" light should come
on about 2 seconds after the pump starts to run and the pump should shut off. If the "EXCESS SLOPE"
light comes on, the pressure switch is bad or the pump pressure is low. If the "EXCESS SLOPE" light
does not come on, the 8100 wire or the I/O module is bad. SEE MP84.3240
1. The "EXCESS SLOPE" light comes on and the pump shuts off. Check the pump pressure.
There is a U shaped tube connecting a manifold fitting to the shuttle valve fitting. Remove the U
shaped tube from the manifold fitting. Attach a 5000 psi pressure gauge to the manifold fitting.
Use a small jumper wire to apply +12 volts to terminal 6 of the pump relay. This will run the pump.
(The ignition must be on.) Pump pressure should be between 3300 psi and 3600 psi. 3500 psi is
the correct pump pressure. If the pump pressure is below 3100 psi, the 3000 psi manifold pressure
switch may not function. Check the voltage at terminal 9 on the pump while the pump is running. If
the voltage at the pump when it is running under load is less than 9 volts, the pump pressure may be
affected. The pump has an adjustable relief valve. If the pump pressure is no lower than 2900 psi,
it may be possible to turn the pressure up enough that the system will function properly. Refer to
MP64.9960 for relief valve adjustment. If the pressure cannot be adjusted to the required level,
replace the pump. If the pump pressure is OK, replace the 3000 psi manifold pressure switch.
SEE MP64.3917, MP64.9980 & MP84.3240
Note: If replacing the 3000 psi pressure switch does not fix the problem, the shuttle valve may be
the issue. Recheck and record the pump pressure as explained above in Section A. Part 1. If pump
pressure is still adequate, reconnect the U shaped tube. Retract all of the jacks. At the manifold,
disconnect one of the jack hoses for a jack that was extending completely. Connect the pressure
gauge to the manifold fitting. Use the valve release nut or valve release cam to manually open the
valve. Use a jumper wire to run the pump as explained above in Section A. Part 1. If the pressure
reading is now lower than the recorded pressure, replace the shuttle valve. If the pressure is still
above 3300 psi, recheck PART 11 section A.1. or contact HWH Technical Service.
2. The "EXCESS SLOPE" light does not come on and the pump continues to run. Unplug the
3000 psi pressure switch and unplug the 32 pin connector at the I/O module. Check for continuity
between the pins for the 8100 pressure switch wire. Repair the wire if necessary. If the 8100 wire
is OK, replace the I/O module. SEE MP84.3170
B. TWO JACKS ARE NOT FULLY EXTENDED BUT THE "EXCESS SLOPE" LIGHT IS COMING ON
AND THE PUMP IS SHUTTING OFF. There are two possibilities. The 3000 psi manifold pressure switch
is coming on too soon or the vehicle weight may be greater than the capacity of the jacks. First, it is
important to measure how far the jacks are extending to make sure they are fully extended. To test the
pressure switch, retract the jacks with the "STORE" button. Install a 5000 psi pressure gauge inline with
the shuttle valve. Put the system in the automatic level mode and monitor the pressure gauge to see
when the "EXCESS SLOPE" light comes on. If the pressure switch is coming on too low, replace the
pressure switch. If the pressure switch is coming on at 3000 psi or more, the capacity of the jacks may
be the issue. Contact HWH Technical Service for assistance. SEE MP64.3917
MULTIPLEX I/O MODULE
PRESSURE
CONTROL
8600 - (BLACK)
PUMP RELAY
MP84.3240
SEE DETAIL (A)
#9
RELAY (A)
MASTER
#4
6230 (RELAY GND)
+12 VOLT
BATTERY
TO
#3
CONTROL
8500 (BLACK)
MASTER RELAY
#2
#1
+
6230 (RELAY GND)
MOTOR
PUMP
PUMP
RELAY (B)
#5
#7
#8
#6
MULTIPLEX I/O MODULE
TO GROUND STUD
DETAIL (A) - TOP VIEW
40 AMP
FUSE
ON PUMP (6230)
SWITCH
1400
4400
6230
6230
A
B
A
B
8100
2400
6230
A
B
3400
6230
A
B
6800
LR
B
A
RF
LF
A
B
B
A
RR
B
A
LR
RR
P.E.D
P.E.D
P.E.D
P.E.D
LF
RF
POWER UNIT
SIDE VIEW
GROUND STUD
07JUN11
MP84.3240
I/O MODULE
SEE DETAIL (A)
DEUTSCH CONNECTOR
SEE ELECTRICAL CONNECTION
DIAGRAM - 725 SERIES
SINGLE STEP LEVELING
SYSTEM
MULTIPLEX
GROUND STUD IN MANIFOLD
SHOWN HERE BENEATH THE
RELAY (A)
MASTER
MOTOR
PUMP
TOP VIEW
RELAY (B)
POWER UNIT
PUMP
PUMP AND MASTER RELAYS
LEVELING SYSTEM HYDRAULIC MANIFOLD
ELECTRICAL CONNECTION DIAGRAM
3000 LB
SWITCH
PRESSURE
50 LB
8101
PRESSURE
MULTIPLEX I/O MODULE
SEE DETAIL (A)
MP84.3240
PUMP RELAY
8600 - (BLACK)
CONTROL
#9
6230 (RELAY GND)
#4
MASTER
RELAY (A)
TO
BATTERY
+12 VOLT
#3
#2
MASTER RELAY
8500 (BLACK)
CONTROL
#1
+
6230 (RELAY GND)
PUMP
MOTOR
RELAY (B)
PUMP
#5
#8
#7
#6
TO GROUND STUD
MULTIPLEX I/O MODULE
DETAIL (A) - TOP VIEW
FUSE
40 AMP
ON PUMP (6230)
SWITCH
B
A
BA
6230
6230
4400
1400
8100
BA
6230
3400
BA
6230
2400
6800
A
B
LR
A
B
B
A
LF
RF
A
B
RR
RR
LR
P.E.D
P.E.D
P.E.D
P.E.D
LF
RF
POWER UNIT
SIDE VIEW
GROUND STUD
MP84.3240
07JUN11
SEE DETAIL (A)
I/O MODULE
DEUTSCH CONNECTOR
SYSTEM
SINGLE STEP LEVELING
DIAGRAM - 725 SERIES
SEE ELECTRICAL CONNECTION
MULTIPLEX
MASTER
RELAY (A)
SHOWN HERE BENEATH THE
GROUND STUD IN MANIFOLD
PUMP
MOTOR
TOP VIEW
PUMP
POWER UNIT
RELAY (B)
ELECTRICAL CONNECTION DIAGRAM
LEVELING SYSTEM HYDRAULIC MANIFOLD
PUMP AND MASTER RELAYS
3000 LB
50 LB
PRESSURE
SWITCH
8101
MP64.3917
WITH VELOCITY
ARE EQUIPPED
MANIFOLDS
NOTE: SOME
SWITCH
LEFT
REAR
shuttle valve and shuttle
to be removed to access
valve tube.
VALVES
PRESSURE
3000PSI
CHECK
HERE
PRESSURE
ASSEMBLY
VELOCITY VALVE
PUMP/MANIFOLD
LR
LF
RF
RR
RIGHT
07JUN11
MP64.3917
REAR
PRESSURE
SWITCH
VALVES (4)
VALVE
SHUTTLE
CHECK
OUTER
50PSI
LOCATION
ALTERNATE
PRESSURE
SWITCH
3000 PSI
BE EQUIPPED WITH VALVE RELEASE NUTS OR
VALVES OR FOUR (4) SMALL VALVES
MANIFOLDS MAY HAVE FOUR (4) LARGE
625/725 SERIES LEVELING SYSTEM
(WITH 4 STRAIGHT-ACTING JACKS)
HYDRAULIC LINE CONNECTION DIAGRAM
IN OPERATOR’S INSTRUCTIONS. VALVES MAY
PROCEDURE FOR MANUAL JACK RETRACTION
VALVE RELEASE, READ AND UNDERSTAND
WITH RELEASE
SMALL VALVES
LARGE AND
may need to be removed
not shown, load center
NOTE: Load center is
FRONT
LEFT
NUTS
BREATHER
BEFORE OPERATING MANUAL
CAP
RELEASE CAMS.
NOTE:
WITH RELEASE
SMALL VALVES
LARGE AND
CAMS
FRONT
RIGHT
MP84.3170
SWITCHED GROUND FROM RIGHT REAR JACK WARNING SWITCH
SWITCHED GROUND FROM LEFT REAR JACK PRESSURE SWITCH
SWITCHED GROUND FROM 3000 PSI MANIFOLD PRESSURE SWITCH
+12 VOLT POWER FOR LEVEL SENSING UNIT
SHIELD WIRE FOR GREEN & YELLOW CAN COMMUNICATION WIRES
GROUND FOR LEVEL SENSING UNIT
SWITCHED GROUND FROM SENSING UNIT - REAR
SWITCHED GROUND FROM LEFT REAR JACK WARNING SWITCH
SWITCHED GROUND FROM SENSING UNIT - RIGHT SIDE
+12 VOLT ACCESSORY POWER FOR I/O MODULE
GROUND FOR JACK WARNING SWITCHES
SWITCHED GROUND FROM LEFT FRONT JACK WARNING SWITCH
SWITCHED GROUND FROM LEFT FRONT JACK PRESSURE SWITCH
SWITCHED GROUND FROM SENSING UNIT - LEFT SIDE
SWITCHED GROUND FROM SENSING UNIT - FRONT
GROUND FROM PARK BRAKE SWITCH
BLACK
BLACK
WHITE
BLACK
BLACK
BLACK
BLACK
BLACK
BLACK
BLACK
BLACK
BLACK
WHITE
C6 AND C7
D1
C8
D3
D4
D6
D7
D8
D5
D2
RED
B4
B5
B7
B8
C2
C3
C4
C5
C1
B6
N/A
RED
6120
0300
1000
0100
0200
9000
1200
6235
3000
8100
N/A
6231
0400
4000
6121
4200
NO CONNECTION
NO CONNECTION
NO CONNECTION
NO CONNECTION
MP84.3170
06JUN11
RIGHT REAR JACK
RIGHT FRONT JACK
ELECTRICAL CONNECTION DIAGRAM
MULTIPLEXED INPUT/OUTPUT MODULE
LED AND WIRE/CONNECTION INFORMATION
LEFT FRONT JACK
LEFT REAR JACK
WIRE DESCRIPTION AND FUNCTION
A1 - (+12 BLACK WIRE 8601) INPUT WHEN EXTENSION DEVICES ROOMS, GEN SLIDE, STEP COVER ECT. ARE USED
CAN HIGH COMMUNICATION WIRE
A LIT RED LED INDICATES THERE SHOULD BE
+12 VOLTS ON THE CORRESPONDING WIRE.
LINK LIGHT: LINK LIGHT FLASHING INDICATES PROPER
COMMUNICATION BETWEEN THE I/O MODULE AND THE
TOUCH PANEL. LINK LIGHT ON SOLID OR OFF INDICATES
SWITCHED GROUND FROM RIGHT FRONT JACK WARNING SWITCH
SWITCHED GROUND FROM RIGHT FRONT JACK PRESSURE SWITCH
SWITCHED GROUND FROM RIGHT REAR JACK PRESSURE SWITCH
SWITCHED GROUND FROM 50 PSI MANIFOLD PRESSURE SWITCH
+12 VOLT POWER TO THE TOUCH PANEL
CAN LOW COMMUNICATION WIRE
GROUND TO THE TOUCH PANEL
NUMBER
NOTE: DUMP AND TRAVEL LEDS PRESENT
WIRE
COLOR
YELLOW
BLACK
BLACK
BLACK
BLACK
GREEN
WHITE
A3 AND A4
A2
A6
A5
A7
A8
B1
B3
B2
RED
FRONT VIEW
OF I/O
MODULE
CONNECTOR
PIN #
N/A
2200
2000
3200
8101
6800
6230
N/A
8
WIRE
2
3
4
5
7 6
BUT NOT ALWAYS USED
A FAILURE.
NO CONNECTION
A
B
C
D
1
LINK LIGHT
MASTER RELAY
PUMP RELAY
DUMP
TRAVEL
GROUND STUD
IMPORTANT: The pump pressure relief should not be adjusted unless a 5000 psi pressure gauge is attached to the
1. Remove the U shaped tube from the manifold fitting, NOT the shuttle valve fitting. Fasten a 5000psi pressure gauge
3. Use a set of small jumper wires to turn the master relay on and run the pump or have someone push any "UP" arrow on the
"MANUAL" side of the leveling system touch panel. If the touch panel is used, the ignition must be in the "ACC." position and
Note: Instruction sheet MI95.74 explains how to run the pump using jumper wires. This sheet is available at
www.hwh.com <http://www.hwh.com> . The sheet is located under "Customer Support & Technical Service"
4. While the pump is running, turn the relief valve set screw clockwise until the pressure gauge shows a minimum of 3300psi
to a maximum of 4000psi. There may be a small amount of leakage at the relief valve while adjusting the pump pressure.
5. Tighten the relief valve jam nut and recheck the pump pressure. Readjust if necessary.
6. Clean and check for any leakage at the relief valve. If there is leakage, contact HWH Corporation technical service.
then "Information Bulletins & Instruction Sheets" (Hydraulic Power Unit Information).
PRESSURE
INSTRUCTION SHEET
PUMP PRESSURE RELIEF ADJUSTMENT
MOTOR
REVERSE FACE
MAY BE LOCATED ON THE
ON SOME PUMPS THIS VALVE
RELIEF VALVE JAM NUT
RELIEF VALVE SET SCREW
ATTACH
HERE
GAUGE
manifold fitting as shown.
2. Loosen the jam nut for the pump adjustable relief valve.
to the manifold fitting.
the park brake must be set.
RR
TANK
LR
LF
RF
07JUN11
MP64.9980
VALVE
SHUTTLE
MP64.9980
