WH R H - HWH Corporation
HW H
R
CORPORATION
SERVICE MANUAL
HWH COMPUTER-CONTROLLED
600 SERIES LEVELING SYSTEM
R
FEATURING:
Touch Panel Leveling Control
Four-Point Air Leveling
With Tag Dump
HWH COMPUTERIZED LEVELING
LEVEL
AIR
EXCESS
SLOPE
NOT IN
PARK/
BRAKE
DUMP
TRAVEL
OFF
RAISE
CAUTION!
UNDERSTAND OPERATOR’S MANUAL BEFORE USING. BLOCK FRAME AND TIRES
SECURELY BEFORE REMOVING TIRES OR CRAWLING UNDER VEHICLE.
HWH CORPORATION
(On I-80, Exit 267 South)
2096 Moscow Road | Moscow, Iowa 52760
Ph: 800/321-3494 (or) 563/724-3396 | Fax: 563/724-3408
www.hwh.com
ML19048/MI91.0015
06MAY04
SECTION 1
N
TIO
SEC
1
E
UBL
O
R
T
TING
O
O
SH
PS
STE
SECTION
2
REPAIR STEPS
SEC
TION
3
DIAG
RAM
S
3 PART FOLDER
HOW TO USE MANUAL
This manual is written in three sections. Section 1 is the Trouble Shooting Steps. Section 2 is the Repair Steps. Section 3 is
the Diagrams. Begin diagnosis of the system with Section 1, the Trouble Shooting Steps. This will give the correct operation
and function of the system. When a malfunction is encountered, the Trouble Shooting Steps will direct you to the proper Repair
Steps in Section 2, the Repair Steps. The Repair Steps are broken into 3 columns, Problem, Solution, and Diagram. In the
proper part under Problems, find the symptom you have encountered. The testing and repair for that problem is in the Solution (center) column. Diagrams for a particular Problem and Solution are in the Diagram (right hand) column. This column will
direct you to the proper diagram in Section 3, Diagrams, for a more detailed view.
Before beginning your repair, it is IMPORTANT to read the CAUTIONS and NOTES AND CHECKS in the first section, TROUBLE
SHOOTING STEPS. In many cases this will save time and mistakes when trouble shooting a system.
This Repair Manual is offered as a guide only. It is impossible to anticipate every problem or combination of problems. This
manual is written in sequential order of the proper operation of the system. The Trouble Shooting Steps must be followed in
order to give correct diagnosis of the problem(s). For any problems encountered that are not addressed in this manual, contact
HWH Corporation for assistance.
NOTE: Diagrams in this manual are of typical systems. There may be plumbing or harness differences. In most cases
this should not effect trouble shooting procedures.
PROCEED WITH TROUBLE SHOOTING GUIDE
MI91.1015
18JUN01
TROUBLE SHOOTING
CAUTIONS!
BLOCK FRAME AND TIRES SECURELY BEFORE CRAWLING UNDER VEHICLE. DO NOT USE AIR SUSPENSION TO SUPPORT VEHICLE WHILE UNDER VEHICLE OR CHANGING TIRES. VEHICLE MAY DROP AND OR
MOVE FORWARD OR BACKWARD WITHOUT WARNING CAUSING INJURY OR DEATH.
DO NOT EXCEED 5 MPH OR TRAVEL LONG DISTANCES WHEN THE SUSPENSION IS NOT AT THE PROPER
RIDE HEIGHT.
SAFETY CLASSES ARE TO BE WORN TO PROTECT EYES FROM DIRT, METAL CHIPS, OIL LEAKS, ETC. FOLLOW
ALL OTHER SHOP SAFETY PRACTICES.
NOTES AND CHECKS
Read and check before preceding with Trouble Shooting Steps.
NOTE: HWH CORPORATION ASSUMES NO LIABILITY
FOR DAMAGES OR INJURIES RESULTING FROM THE
INSTALLATION OR REPAIR OF THIS PRODUCT.
1. The trouble shooting guide must be followed in order. Problems checked for in one step are assumed correct and not
checked again in following steps.
2. Batteries should be in good condition and fully charged. Low
voltage can cause erratic operation.
3. Do not replace the control box unless the repair steps say
to replace it. Otherwise the malfunctions may damage the
new control box.
4. If the control box is removed, +12 ignition power must be
applied to the travel solenoid wires (GRAY) 1700 in the front
and (GRAY) 3700 in the rear air harnesses. This will allow the
height control valve to function. See MP85451F of section (3)
Diagrams.
This manual is intended for use by experienced mechanics
with knowledge of air suspension and automotive electrical
systems. People with little or no experience with HWH
leveling systems should contact HWH technical service
(800-321-3494) before beginning. Special attention should
be given to all cautions, wiring, and air diagrams.
Special note: When installing a new control box, make
sure the box is properly grounded before applying power
to the system.
Suggested tools for trouble shooting the HWH leveling systems:
JUMPER WIRES(UP TO 10 GAUGE)
MULTI-METER
12 VOLT TEST LIGHT
PROCEED WITH THE TROUBLE
SHOOTING STEPS ON THE
FOLLOWING PAGE
MI91.1021
03FEB99
CONTROL IDENTIFICATION
"EXCESS SLOPE"
Indicator light
"TRAVEL"
Indicator light
"NOT IN PARK"
Indicator light
AIR OPERATION
Indicator light
LOWER FRONT
Manual Button
RAISE FRONT
Manual button
"AIR" BUTTON
HWH COMPUTERIZED LEVELING
AIR DUMP
Indicator light
LEVEL
"DUMP" BUTTON
AIR
AIR BAG
Indicator light
(4 red)
RAISE RIGHT SIDE
Manual button
NOT IN
PARK/
BRAKE
DUMP
RAISE
Indicator light
EXCESS
SLOPE
LOWER RIGHT SIDE
Manual button
TRAVEL
OFF
RAISE
CAUTION!
UNDERSTAND OPERATOR’S MANUAL BEFORE USING. BLOCK FRAME AND TIRES
SECURELY BEFORE REMOVING TIRES OR CRAWLING UNDER VEHICLE.
"OFF" BUTTON
LEVEL SENSING
Indicator light
(4 yellow)
RAISE REAR
Manual button
"RAISE"
Button
RAISE LEFT SIDE
Manual button
LOWER LEFT SIDE
Manual button
LOWER REAR
Manual button
CONTROL FUNCTIONS
CONTROL BUTTONS
"AIR" Button - This button is the system on button and automatic
operation button.
"EXCESS SLOPE" light - This light will be on if the leveling
system can NOT level the coach.
"OFF" Button - This button will turn the system OFF but does
NOT control power to the "DUMP" or "RAISE" buttons.
"TRAVEL" light - This light will be on if the leveling system is off
and the coach suspension is operable.
"DUMP" Button - This button will lower the whole coach by
dumping air from the suspension system.
AIR BAG lights- These lights will be on when the system is on
if the ignition is on. The coach should NOT be moved while
these lights are on.
"RAISE" Button - This button will raise the whole coach
by adding air to the suspension system.
UP ARROWS - These are the RAISE manual buttons.
DOWN ARROWS - These are the LOWER manual buttons.
LEVEL SENSING lights- One or two yellow lights can be on
indicating that side or end of the coach is low.
"NOT IN PARK/BRAKE" light- This light will be on if the "AIR"
button is pushed and the park brake is not set.
INDICATOR LIGHTS
AIR OPERATION light - This light will be on when the system
is on, and flash during automatic leveling.
AIR DUMP light - This light will flash when the "DUMP" button
is being pushed.
RAISE light - This light will flash when the "RAISE" button
is being pushed.
MI91.1026
25JUL95
TROUBLE SHOOTING STEPS
NOTE: The coach should be at the proper ride height before
starting the Trouble Shooting Steps.
1. Make sure the transmission is in the recommended position
for parking and the park brake is set. The ignition switch should
be in the "OFF" position. If any touch panel lights are on, see
Part 1 of the Repair Steps.
AUTOMATIC LEVELING
6. Start the coach engine. Set the park brake. Push the "AIR"
button one time to turn the system on. Push the "AIR" button
a second time. This will start automatic leveling. The following
should occur:
a. The four red warning lights will be on.
2. Turn the ignition switch to "ON". Only the green "TRAVEL" b.
light should be lit. If this is not so, see Part 2 of the Repair Steps.
c.
3. Press the "AIR" button one time. The "ON" indicator light
should come on. One or two yellow level indicator lights may
d.
come on. The four red AIR BAG indicator lights and the Master
Warning Light should be on. The "TRAVEL" light should NOT
be on. If this is not correct see Part 3 of the Repair Steps.
4.MANUAL OPERATION: With the system on, the manual up
and down arrows should function. These buttons are momentary buttons. Releasing the button will stop the function. Each
set of arrows operate pairs of air bags, front, rear, or sides.
There are two air manifolds. One for the front air bags and one
for the rear air bags. Each manifold has six air solenoid valves.
A right and left raise valve, a right and left lower valve and a
right and left travel valve. (See MP75.4515). The travel solenoids are tied together electrically in the harnesses and should
be on if the ignition is in the "ON" position and the system is
off. The front manifold has a right and left air pressure switch.
When the pressure in one front air bag drops to approximately
10 psi, the opposite side front air bags will be inhibited from
exhausting any more air whether in automatic leveling, pushing
a down arrow in manual leveling or pushing the "DUMP" button. The rear manifold has one pressure switch for both sides
and will not interfere with the function of the leveling system.
The pressure switches complete ground signals. When an up
arrow is pushed a +12 signal is sent to the auxiliary air compressor and the corresponding raise solenoid on the air manifolds.
The raise valves open the air bags to inflate lifting the coach.
The air compressor will only run as the system pressure drops.
When a down arrow is pushed a +12 signal is sent to the corresponding lower solenoids. The lower valves will open allowing the air bags to deflate lowering the coach.
Test each set of up and down arrows checking that the appropriate air bags will inflate and deflate and that the auxiliary
compressor will run during the raise function. If there is any
malfunction see Part 4 of the REPAIR STEPS.
5. SENSING UNIT CHECK: Using a bubble level inside the
coach, level the coach using the up and down arrow buttons.
All yellow indicator lights should be off at this time. If not, the
sensing unit may need to be adjusted. A yellow light indicates
that side or end of the coach is low. Check that all yellow lights
can be made to come on (at different times) by raising and /or
lowering the ends and sides of the coach. If the ground is too
uneven the coach may need to be moved to complete this test.
For sensor adjustment procedure see MP85.9505.
For sensor testing see Part 5 of the REPAIR STEPS.
The indicator light above the "AIR" button will start to flash.
The master warning light will be on.
The coach will automatically level itself. The leveling procedure is as follows:
If there are no yellow lights the control box will go directly
into a sleep mode.
If there are yellow lights on, leveling will start in a down
mode, deflating air bags opposite to lit yellow level indicator lights. After 2 minutes if the coach is not level, the computer will switch to the "UP" mode, inflating air bags according to lit yellow lights. During any raise (UP) function
the compressor may run. When all the yellow lights are
are out, the control box goes into the sleep mode.
SLEEP MODE: After leveling the coach the control box
will remain on but inactive for 30 minutes. After 30 minutes
the control box will wake up and monitor the yellow lights
until leveling is needed. If a light is on or comes on and
remains on for 60 seconds, the control box will relevel the
coach using the original leveling procedure. After leveling
the vehicle the control box will return to the sleep mode.
EXCESS SLOPE: During the leveling mode, either initially or after a sleep mode, if the coach cannot be leveled
in 15 minutes the control box will stop all operations, and
the "EXCESS SLOPE" indicator will come on. The box will
will remain on until the "OFF" button is pushed, but will not
go into a sleep mode.
If any of the above does not occur, see Part 6 of the
REPAIR STEPS.
7. TRAVEL MODE: With the ignition on and leveling system
off, the coach should return to the proper travel height. The
travel solenoids are energized allowing the height control valves
to function. NOTE: If the ignition is on and the park brake is
released the leveling system should turn off and the coach
should return to ride height. If the coach will not return to the
proper ride height see part 7 of the REPAIR STEPS.
8. DUMP AND RAISE BUTTONS The "DUMP" AND "RAISE"
buttons are for operator convenience. They allow the coach to
temporarily be raised or lowered to clear obstacles while moving. These are momentary buttons. When released, the coach
will return to ride height if the ignition is on. These buttons will
operate with the system on or off, and the ignition on or off. If the
system is on, the system will turn off when the button is released.
The "DUMP" and "RAISE" button will lower or raise the whole
From this point on, it is assumed the system is fully funccoach. If they are not working correctly see Part 8 of the REPAIR
tional in the manual mode. Whenever a malfunction occurs, STEPS.
revert to the manual operation and check for correct funcDo not exceed 5 mph or travel long distioning. If a problem is found in manual operation, trouble
tances when using these buttons or if the coach is not at
shoot the problem using the preceding steps. Remember,
low volts can cause erratic performance and damage com- the proper travel height.
ponents.
MI91.1031
CAUTION:
16JUN00
TAG DUMP
TO TAG
DUMP
SWITCH
TAG
TRAVEL
3701 (GRAY)
+12 TO TAG
DUMP SWITCH
1700 (BLACK)
TO REAR
TAG AIR
HARNESS
LR TAG
DUMP/LOWER
4601 (PURPLE)
TAG LIFT
NOT USED
3800 (RED)
TAG TRAVEL
3701 (GRAY)
RR TAG
DUMP/LOWER
3601 (BROWN)
TAG DUMP/
LOWER
3800 (YELLOW)
NOTE: THE (4) DIGIT WIRE NUMBER
SUPERSEDES ANY AND ALL WIRE COLORS.
During Manual or Automatic leveling or when using the
"DUMP" button on the leveling system Touch Panel, the
Right Tag Dump/Lower valve is electronically tied to the
Right Rear Drive Axle Lower valve. The Left Tag Dump/
Lower valve is electronically tied to the Left Rear Drive
Axle Lower valve.
Power to the Right Tag and Left Tag Dump/Lower valves
will go through the 6-pin UML connector during LEVELING
and "DUMP" procedures.
TRAVEL
RAISE
TAG AXLE
AIR MANIFOLD
RAISE
When the Tag Dump switch is in the DUMP position, there
will be NO +12 power to the 3701 (GRAY) Travel wire in the
3 or 6-pin UML connectors. There will be +12 power on the
3800 (YELLOW) Tag Dump wire in the 3-pin UML connector.
There will be +12 power on the 3601 (BROWN) wire and the
4601 (PURPLE) wire in the 6-pin UML connector. There will
be power to both Tag Lower valves on the Tag Axle manifold.
The Front air manifold and the Rear air manifold should stay
in the TRAVEL mode.
LOWER
When the Tag Dump switch is in the Travel position, there
will be +12 power on the 3701 (GRAY) Travel wire in the
3-pin UML connector. There will be +12 power on the
3701 (GRAY) Travel wire in the 6-pin UML connector.
There should be +12 power to the Tag Axle Travel valves.
TRAVEL
The Tag Dump switch is supplied by the Coach Manufacturer.
The 1700 (BLACK) wire in the 3-pin UML connector supplies
+12 power to the tag dump switch when the leveling system
is in the "TRAVEL" mode. The vehicle ignition must be ON.
LOWER
During the normal travel mode, the Tag Travel valves are
tied electrically to the Front and Rear air manifold Travel
valves. The Travel Fuse also protects the Tag Manifold
Travel valves.
TAG AXLE
AIR MANIFOLD
(SIDE VIEW)
TRAVEL SOL.
LOWER SOL.
RAISE SOL.
MI91.1033
09OCT02
SECTION 2
600 SERIES
REPAIR MANUAL
HWH COMPUTER-CONTROLED
LEVELING SYSTEM
TOUCH PANEL CONTROL
4 - POINT AIR LEVELING
BEGIN WITH SECTION 1
FOR COACHES WITH A TAG AXLE
USING THE HWH TAG AXLE DUMP
CONTROL BOX, READ THE TAG DUMP PAGE
IN SECTION 1 BEFORE CONTINUING
MI91.2011
26SEP02
REPAIR STEPS
PROBLEM
SOLUTION
Part 1
Touch panel has
indicator lights on
with the ignition
switch off.
If the "ON" indicator light is on, press the "OFF" button. If the "ON"
light or any other light remains on, replace the control box. If the
"ON" light is not on and any other light is on, replace the control box.
FIGURES
AIR OPERATION
indicator light
HWH COMPUTERIZED LEVELING
LEVEL
TRAVEL
OFF
RAISE
CAUTION!
UNDERSTAND OPERATOR’S MANUAL BEFORE USING. BLOCK FRAME AND TIRES
SECURELY BEFORE REMOVING TIRES OR CRAWLING UNDER VEHICLE.
REFER TO MI91.1026
OF SECTION I
HWH COMPUTERIZED LEVELING
LEVEL
AIR
NOT IN
PARK/
BRAKE
DUMP
Whenever the ignition switch is "ON" one of these lights will be lit
but never both at the same time. If neither light is on, check the
power to the control box. The (YELLOW) 6110 wire in the power harness will have +12 volts with the ignition in the "ON" position. The (RED)
6100 wire should have +12 volts with the ignition in any position. If the
(YELLOW) 6110 wire has power replace the control box. If not, trace
the (YELLOW) 6110 wire to its source.
EXCESS
SLOPE
TRAVEL
OFF
RAISE
CAUTION!
UNDERSTAND OPERATOR’S MANUAL BEFORE USING. BLOCK FRAME AND TIRES
SECURELY BEFORE REMOVING TIRES OR CRAWLING UNDER VEHICLE.
REFER TO MI91.1026
OF SECTION I
NOTE: If the vehicle is not equipped
with a master warning light, proceed to
Part 2b.
1
2
5
3
15
4
15
5
5
6
5
POWER
HARNESS
a. The green
"TRAVEL" light nor
the master warning
light is lit.
EXCESS
SLOPE
NOT IN
PARK/
BRAKE
DUMP
"OFF" BUTTON
"TRAVEL"
indicator light
Part 2
With the ignition
switch on:
AIR
BATTERY-RED
IGNITION-YELLOW
5
7
5
8
5
9
10
5
11
7.5
5
REFER TO MP85.4510
With the system off and the ignition in the "ON" position, the master
warning light will come on and the "TRAVEL" light will go out if an air
bag has low pressure. If the coach is not at the proper ride height
start the coach engine and build up air pressure. The master warning
light should go out and the "TRAVEL" light should come on as the
coach returns to the proper ride height. If the coach will not return to
the proper travel height see Section 7 of the TROUBLE SHOOTING
STEPS. If the master warning light is lit, the "TRAVEL" light is not on
and the coach is at the proper ride height there is a bad pressure
switch or a shorted wire for one of the air manifolds.
PRESSURE
SWITCH
REFER TO MP75.4520
There are two pressure switches on the front manifold and one pressure switch on the rear manifold.
Unplug the pressure switch at the rear manifold. If the master warning light goes out and the "TRAVEL" light comes on replace the pressure switch.
If the lights do not work properly, unplug either pressure switch on
the front manifold. If the lights are correct replace that switch. If the
lights are not correct unplug the other pressure switch. If the lights
are correct replace that pressure switch. If the lights are still not correct go to the control box. Unplug the front pressure switch harness.
If the lights are correct the problem is in the harness. If the lights are
not correct, unplug the rear air harness. If the lights are correct the
(YELLOW) 3215 wire in the harness is shorted to ground. If the lights
still are not correct, replace the control box.
PRESSURE
SWITCH
REFER TO MP75.4515
1
2
5
5
3
15
4
15
5
6
7
8
POWER
HARNESS
b. The master
warning light is lit
and/or the "travel"
light is not lit.
5
5
5
5
9
10
5
11
7.5
5
PRESSURE SW INPUTS
FROM FRONT AIR HARNESS
LF AIR PRESSURE SW-BLACK
RF AIR PRESSURE SW-ORANGE
REFER TO MP85.4510
MI91.203B
13APR00
REPAIR STEPS
PROBLEM
SOLUTION
DIAGRAMS
Part 3
After pushing the
"AIR" button one
time:
3
COMPRESSOR
15
a. The system will
not turn on and no
lights except the
TRAVEL light are
on.
Check the battery fuse. If it is not blown the control box, touch panel,
or cable is bad. If the battery fuse is blown, replace the fuse, unplug
the compressor wire then press the "AIR" button again. If the fuse
blows again replace the control box. If the fuse does not blow and
the system turns on, the compressor wire is probably shorted to
ground.
b. All of the panel
lights come on and
stay on.
The microprocessor is bad. Replace the control box.
c. The on indicator
light will not stay on
and the NOT IN
PARK/BRAKE light
comes on while the
"AIR" button is being pushed.
Make sure the park brake is set. Check for a ground on the (BLUE)
9000 Park/Brake Sensor wire. If a ground is present, replace the control box. If a ground is not present trace the (BLUE) 9000 wire and
check its connection. Check the park brake switch.
COMPRESSOR - BLACK
FROM REAR AIR HARNESS
REFER TO MP85.4510
SEE CONTROL
BOX DIAGRAM
TO BRAKE LIGHT
ON DASH
GROUND
STUD
WHITE
PARK BRAKE
SWITCH
PARK
BRAKE
BLUE
POWER
HARNESS
REFER TO MP85.453F
d. Opposite yellow
lights come on.
Unplug the sensing unit cable. There are five pins. The pin for the
white wire is the ground for the sensing unit. The other four pins are
for the front, rear, left and right side yellow lights. Ground each individual pin. Only one light should come on per pin. If more than one
light comes on, replace the control box. If only one light comes on,
replace the sensing unit.
1
2
5
3
15
4
15
5
WHITE-(GROUND)
YELLOW-LEFT SIDE
BLACK-FRONT
GREEN-RIGHT SIDE
RED-REAR
5
6
LEVEL SENSING
UNIT INPUTS
7
8
5
5
5
5
9
10
5
11
7.5
5
REFER TO MP85.4510
e. With the "ON"
indicator light lit, the
TRAVEL light will
not go out.
The travel light should not be on when the system is on. Replace
the control box.
"TRAVEL"
indicator light
AIR OPERATION
indicator light
HWH COMPUTERIZED LEVELING
LEVEL
AIR
EXCESS
SLOPE
NOT IN
PARK/
BRAKE
DUMP
TRAVEL
OFF
RAISE
CAUTION!
UNDERSTAND OPERATOR’S MANUAL BEFORE USING. BLOCK FRAME AND TIRES
SECURELY BEFORE REMOVING TIRES OR CRAWLING UNDER VEHICLE.
REFER TO MI91.1026
OF SECTION I
MI91.203D
13APR00
REPAIR STEPS
PROBLEM
SOLUTION
DIAGRAMS
Part 3
continued
MASTER WARNING
INDICATOR OUTPUT
PURPLE FROM
POWER HARNESS
1
2
5
3
15
4
15
5
5
6
5
5
7
5
8
f. The master
warning light is
not on.
The (PURPLE) 7699 wire from the master warning indicator output
should be a ground when the the system is on and the ignition is in the
"ON" position. If not, replace the control box. If power is present, check
the (PURPLE) 7699 wire at the light. Check the ground for the light or
replace the bulb.
5
9
10
5
11
7.5
5
REFER TO MP85.4510
Part 4
When pushing an
up or down arrow:
NOTE: The coach
should be at proper
ride height when
testing down arrows.
Check that the exhaust ports of the air manifold are not plugged.
Check the corresponding fuse for the bag that is not exhausting air.
If the fuse is blown, the valve or the wire to the valve is shorted to
ground. If the fuse is not blown, check the corresponding pin in the
box for the valve.
If power is not present. Unplug the opposite front pressure switch
and retry. If power is not present replace the control box. (Check that
the pressure switch wires are not shorted to ground). If power is
present the pressure switch that is unplugged is closed. If there is
more than 20 psi in the air bag the pressure switch should be replaced.
If power is present on the pin. With the pressure switch wires plugged in, the problem is the wire to the valve, the ground for the valve,
or the valve. Check for power in the harness plug. If it is a 2 - wire
plug check between the two pins in the plug. If it is a 1 - wire plug,
check between the plug and ground. If power is present check the
ground for the solenoid if it is a 1 - wire plug. Replace the valve if
power is present and the ground is OK. If a 2 - wire plug is used the
white wire is ground, Check for power between the (colored) black wire and
a frame member. If power is present repair the ground wire. If power
is not present repair the (colored) black wire.
EXHAUSTS
PORT (2)
LOWER SOLENOID
VALVE (2) RIGHT & LEFT
REFER TO MP75.4515
FRONT
AIR
HARNESS
a. A front bag will
not deflate when
pushing a front or
side down arrow.
PRESSURE
SWITCH (2)
1
2
5
3
4
5
6
7
8
9
10
11
5
PRESSURE SW INPUTS
FROM FRONT AIR HARNESS
LF AIR PRESSURE SW-BLACK
RF AIR PRESSURE SW-ORANGE
GROUND WIRES FROM
FRONT AIR HARNESS (2)
REFER TO MP85.4510
MI91.203F
13APR00
REPAIR STEPS
PROBLEM
SOLUTION
DIAGRAMS
Part 4
continued
b. A rear bag will
not deflate when
pushing a rear or
side down arrows.
The pressure switch will not interfere when deflating the rear air bags.
Check the fuse for the appropriate lower solenoid valve. If the fuse is
blown the solenoid valve or the power wire for the solenoid valve is
shorted.
If the fuse is not blown check for power on the corresponding pin in
the control box. If power is not present, replace the control box. If
power is present on the pin, the problem is the wire to the valve,
the ground for the valve, or the valve. Check for power in the harness plug. If it is a 2 - wire plug check between the two pins in the
plug. If it is a 1 - wire plug check between the plug and ground. If
power is present check the ground for the solenoid if it is a 1 - wire
plug. Replace the valve if power is present and the ground is OK. If
power is not present a wire or connection is bad. If a 2-wire plug is
used the white wire is ground. Check for power between the (colored)
black wire and a frame member. If power is present repair the ground
wire. If power is not present repair the (colored) black wire.
EXHAUSTS
PORT (2)
LOWER SOLENOID
VALVE (2) RIGHT & LEFT
REFER TO MP75.4515
1
2
3
4
5
5
REAR AIR
HARNESS
5
6
7
8
9
10
11
GROUND WIRES FROM
REAR AIR HARNESS (2)
REFER TO MP85.4510
c. Diagonal air
bags deflate or inflate when a side
arrow is pushed.
If diagonal bags such as left front and right rear deflate or inflate
when a side arrow is pushed the wiring or plumbing connection are
switched. Check the diagrams and redo connections according to
the diagrams.
REFER TO MP75.450D
REFER TO MP85.453F
MI91.203H
13APR00
REPAIR STEPS
PROBLEM
SOLUTION
DIAGRAMS
Part 4
continued
Check the appropriate fuse for that raise solenoid valve. If the fuse
is blown the valve, or the power wire to the valve is shorted.
RAISE SOLENOID
VALVE (2) RIGHT & LEFT
REFER TO MP75.4515
RAISE SOLENOID
VALVE (2) RIGHT & LEFT
REFER TO MP75.4520
FRONT
AIR
HARNESS
If the fuse is not blown check for power on the corresponding pin in
the control box. If power is not present, replace the control box. If
power is present on the pin, the problem is the wire to the valve,
the ground for the valve, or the valve. Check for power in the harness plug. If it is a 2 - wire plug check between the two pins in the
plug. If it is a 1 - wire plug check between the plug and ground. If
power is present check the ground for the solenoid if it is a 1 - wire
plug. Replace the valve if power is present and the ground is OK. If
power is not present a wire or connection is bad. If a 2-wire plug is
used the white wire is ground. Check for power between the (colored)
black wire and a frame member. If power is present repair the ground
wire. If power is not present repair the (colored) black wire.
1
2
LEFT FRONT RAISE-GREEN
5
3
4
5
6
7
5
8
5
9
10
5
REAR AIR
HARNESS
d. Air bags will not
inflate when an up
arrow is pushed.
LEFT FRONT RAISE-GREEN
11
GROUND
WIRES FROM
REAR AIR
HARNESS (2)
GROUND WIRES FROM
FRONT AIR HARNESS (2)
REFER TO MP85.4510
MI91.203J
13APR00
REPAIR STEPS
DIAGRAMS
Part 4
continued
e. The compressor will not run
when pushing up
arrow.
NOTE: If the air
system is fully pressurized, the compressor should not
run. Pumping the
brake pedal several times will reduce pressure in
the system allowing the compressor to run.
The (BLACK) 9700 wire for the air compressor is in the rear air manifold harness. It goes to the 3 pin compressor plug in the box. When
an up arrow is pushed, there should be +12 power on this wire.
1
2
5
3
15
4
15
5
5
6
5
7
5
COMPRESSOR
SOLUTION
5
8
5
9
10
5
11
7.5
COMPRESSOR-BLACK
FROM REAR AIR HARNESS
REAR AIR
HARNESS
PROBLEM
5
Check the corresponding pin in the box. If +12 is not present replace
the control box.
REFER TO MP85.4510
NOTE: There is no fuse for the compressor wire. The power comes
from the battery fuse in the control box. If the battery fuse is blown
the system will not turn on.
If +12 compressor power is present at the control box, check for
power at the compressor. The compressor harness plug (A) should
have +12 power when an up arrow is pushed. If not the wire is bad.
If power is present check the +12 battery power (B) at terminal 1 of
the 12 volt relay (C) on the compressor assembly. That wire should
be fused. If there is no power check the fuse, the wire, the connections and the source. If there is power to the relay and the compressor will not run, the problem is the pressure switch (D), the relay (C)
or the compressor motor (E).
Jump power from terminal 1 to Terminal 2. If the compressor does
not run, check the ground connections at terminal 7. If OK the compressor should be replaced. If the compressor does run, jump
power from terminal 1 to terminal 3, If the compressor does not run
check the ground for terminal 4. If OK, replace the relay (C). If the
compressor runs, check for power at Terminal 5. If power is not present, the short brown lead (F) or the connection to the compressor
harness (A) is bad. If power is present, replace the pressure switch.
(D).
GRAY FROM
AIR SOLENOID
FUSE
15 AMP
12 VOLT RELAY (2)
+12 SIGNAL FROM
PRESSURE SWITCH
TO +12 BATT
POWER
GROUND
CHECK VALVE (4)
AIR LINE TO SUSPENSION
FLOW
PRESSURE SWITCH (1)
NORMALLY CLOSED
(OPEN AT 115 P.S.I.)
(CLOSED AT 105 P.S.I.)
AIR FILTER
NORMALLY OPEN AIR SOLENOID (3)
GROUND TO RELAY MOUNTING BOLT
BLACK-COMPRESSOR HARNESS FROM CONTROL BOX
REFER TO MP75.4525
COMPRESSOR
HARNESS FROM
CONTROL BOX
BLACK (+12 SIGNAL)
(A)
PRESSURE SWITCH (D)
OPEN 115 PSI
CLOSE 105 PSI
6
WHITE
GROUND
5
BROWN +12 (F)
ORANGE
3
4
12 VOLT
ESSEX
RELAY
(C)
7
BLACK ( GROUND )
1
RELAY MTG. BOLT
RED +12
2
COMPRESSOR MOTOR
(E)
FUSE
15 AMP
(B)
GRAY (GROUND)
GRAY (+12 SIGNAL)
RED
NORMALLY OPEN
12 VOLT AIR SOLENOID
+12 VOLT
BATTERY POWER
REFER TO MP85.4525
Part 5
Yellow level indicator lights, will
not work properly.
Unplug the sensing unit from the control box. Connect the test light
to +12. The pin for the white wire of the sensing unit is a ground.
Check the pin with the test light. If a ground is not present, replace
the control box, If ground is present, connect the test light to ground.
Touch the four pins for the color coded wire. Each pin will light one
yellow light. If this is so, the problem is the sensing unit. If not, replace the control box.
Check that the sensing unit is mounted correctly according to the
sticker on the sensing unit.
1
2
5
3
15
4
15
5
BATTERY-RED
IGNITION-YELLOW
BATTERY-RED
IGNITION-YELLOW
BATTERY-RED
LEVEL SENSING
UNIT INPUTS
5
6
7
8
5
5
5
5
9
10
5
11
7.5
5
REFER TO MP85.4510
REAR
CROSS MTG (BI-AXIS) SENSING UNIT
THIS
SIDE
UP
REFER TO MP85.9505
MI91.203L
13APR00
REPAIR STEPS
PROBLEM
SOLUTION
DIAGRAMS
AUTOMATIC LEVELING
The system will
not shut off if the
park brake is
released.
PARK BRAKE SENSOR
FROM POWER HARNESS (BLUE) 9000
FRONT
AIR
HARNESS
Part 7
The coach will not
return to the proper travel height
with the ignition
on and the system
off.
If the system will not function properly in the automatic mode, check
steps 1 thru 5. If the system works manually, replace the control box.
Remember low voltage situations and poor ground connections will
cause erratic leveling.
Check the fuse for the travel solenoids. A blown fuse indicates a
shorted wire or solenoid valve. Unplug one air harness at a time to
determine which wire or manifold is shorted. Then unplug the travel
solenoid to determine a bad wire or valve.
If the fuse is not blown, check the corresponding pins in the control
box for the travel solenoids. If +12 power is not present, replace the
control box. If power is present check for power at the manifolds.
Then replace the solenoid valve for any bag that will not reinflate.
With the system on, the ignition on and the park brake released,
unplug the park brake connection from the control box. If the system
remains on, replace the control box. If the system turns off, there is
a constant ground on the park brake wire. Check that the park brake
wire is properly connected to the park brake switch and that the park
brake switch is working properly.
1
2
BATTERY-RED
3
4
BATTERY-RED
IGNITION-YELLOW
5
6
POWER
HARNESS
Part 6
After pushing the
"AIR" button twice
the system will not
level properly.
7
8
REAR TRAVEL SOLENOID-GRAY
9
10
11
7.5
REFER TO MP85.4510
TRAVEL SOLENOID
VALVE (2) RIGHT & LEFT
REFER TO MP75.4515
TRAVEL SOLENOID
VALVE (2) RIGHT & LEFT
REFER TO MP75.4520
Part 8
The coach will not
raise or lower
when using the
"RAISE" and
"DUMP" button.
The coach will not
return to travel
height when the
button is released.
These buttons are extensions of the up and down arrows. Check
Part 4 a, b, and d of this section. If these function properly replace
the control box or touch pad.
Recheck Part 7 of this section. If it is OK there may be a problem
with the height control valves.
MI91.203N
16JUN00
AIR LINE CONNECTION
DIAGRAM
FRONT MANIFOLD
COMPRESSOR
FRONT
VEHICLE
SUSPENSION
AIR SUPPLY
C
AIR BAG
V
NOTE: DOTTED LINES MAY
OR MAY NOT BE USED.
SECOND AIR BAG MAY
BE TIED TO THE LINE
FOR THE FIRST AIR BAG
REAR MANIFOLD
LINE FROM HEIGHT
CONTROL VALVE
LINE TO AIR BAGS
AIR SUPPLY
C
C
V
V
HEIGHT CONTROL
VALVE (3 PLACES)
MANIFOLDS ARE MOUNTED TO MAIN
CROSS MEMBERS. LEAVE AMPLE
CLEARANCE FOR CONNECTION OF
HOSES TO FITTINGS.
MP75.450D
03FEB99
AIR LEVEL SCHEMATIC
4-POINT LEVELING W/AIR COMPRESSOR
PRESSURE SWITCHES FRONT AND REAR
SEE AIR
COMPRESSOR
FRONT HEIGHT
CONTROL VALVE
(HCV)
VEHICLE
SUSPENSION
AIR SUPPLY
EXH
FRONT MANIFOLD ASSY.
AIR
BAG
TRAV.
TRAV.
EXH
AIR
BAG
AIR
BAG
EXH
LOWER
RAISE
LOWER
RAISE
AIR
BAG
PRESSURE
REGULATOR
REAR MANIFOLD ASSY.
EXH
LR HEIGHT
CONTROL
VALVE
(HCV)
EXH
AIR
BAG
TRAV.
TRAV.
EXH
AIR
BAG
AIR
BAG
EXH
LOWER
RAISE
LOWER
RR HEIGHT
CONTROL
VALVE
(HCV)
AIR
BAG
RAISE
MP75.450G
06AUG99
AIR SOLENOID MANIFOLD
6 VALVE WITH TWO PRESSURE SWITCHES
3.400"
LINE FROM HEIGHT
CONTROL VALVE
LINE TO AIR BAGS
E
S
WE
ES
LO
PR
LINE TO AIR BAGS
RAIS
TRAVEL
PRESSURE SWITCH
R
SW
AIR SUPPLY
CHECK VALVE
E
IS
RA
EL
AV
TR
LOWER
W
SS S
PRE
REAR VIEW
MOUNTING HOLES
LINE FROM HEIGHT
CONTROL VALVE (2 MAY BE
TEE’D TOGETHER IF ONE
HCV IS USED)
TRAVEL SOLENOID
VALVE (2) RIGHT & LEFT
LINE TO AIR BAGS
(2-LEFT & RIGHT)
LOWER SOLENOID
VALVE (2) RIGHT& LEFT
PRESSURE SWITCH (2)
EXHAUSTS PORT (2)
LINE TO AIR BAGS
(2-LEFT & RIGHT)
RAISE SOLENOID
VALVE (2) RIGHT & LEFT
AIR SUPPLY (1)
CHECK VALVE (2)
SIDE VIEW
MP75.4515
21APR97
AIR SOLENOID MANIFOLD
6 VALVE WITH ONE PRESSURE SWITCH
3.400"
LINE FROM HEIGHT
CONTROL VALVE
LINE TO AIR BAGS
LINE TO AIR BAGS
AIR SUPPLY
CHECK VALVE
REAR VIEW
MOUNTING HOLES
LINE FROM HEIGHT
CONTROL VALVE (2 MAY BE
TEE’D TOGETHER IF ONE
HCV IS USED)
TRAVEL SOLENOID
VALVE (2) RIGHT & LEFT
LINE TO AIR BAGS
(2-LEFT & RIGHT)
LOWER SOLENOID
VALVE (2) RIGHT& LEFT
EXHAUSTS PORT (2)
LINE TO AIR BAGS
(2-LEFT & RIGHT)
RAISE SOLENOID
VALVE (2) RIGHT & LEFT
AIR SUPPLY (1)
CHECK VALVE (2)
PRESSURE SWITCH
SIDE VIEW
MP75.4520
04SEP97
COMPRESSOR DIAGRAM
GRAY FROM
AIR SOLENOID
FUSE
15 AMP
12 VOLT RELAY (2)
+12 SIGNAL FROM
PRESSURE SWITCH
TO +12 BATTERY
POWER - 6100
GROUND
NOTE: THE (4) DIGIT WIRE
NUMBER SUPERSEDES
ANY AND ALL WIRE COLORS.
CHECK VALVE (4)
AIR LINE TO SUSPENSION
FLOW
PRESSURE SWITCH (1)
NORMALLY CLOSED
(OPEN AT 115 P.S.I.)
(CLOSED AT 105 P.S.I.)
AIR FILTER
NORMALLY OPEN AIR SOLENOID (3)
GROUND TO RELAY MOUNTING BOLT
COMPRESSOR HARNESS FROM CONTROL BOX - (BLACK) 9700
The control box sends a +12 signal to the normaly closed pressure switch (1). If the pressure is low, the 12 volt relay (2)
will energize and the compressor will run. The normally open
air solenoid (3) will close allowing the compressor to build pressure. When the pressure builds to 115 P.S.I. the pressure
switch will open, stopping the air compressor.
The normaly open air solenoid (3) will open, allowing internal
pressure & moisture to bleed off. The check valve (4) will keep
the suspension air from bleeding back to the compressor. As
air pressure drops below 105 P.S.I. the compressor will start.
MP75.4525
03FEB99
5
3
15
4
15
PARK
BRAKE
LF RAISE - (GREEN) 1500
LF LOWER - (RED) 1600
FRONT TRAVEL - (GRAY) 1700
RF LOWER - (BLUE) 2600
RF RAISE - (YELLOW) 2500
5
5
6
5
7
5
8
5
9
10
5
11
7.5
5
5
REAR AIR
HARNESS
LEVEL SENSING
UNIT INPUTS
MODULAR CABLE
FROM TOUCH
PANEL
PARK BRAKE SENSOR
FROM POWER HARNESS (BLUE) 9000
COMPRESSOR
WHITE-(GROUND)
YELLOW-LEFT SIDE
BLACK-FRONT
GREEN-RIGHT SIDE
RED-REAR
1
2
POWER
HARNESS
MASTER WARNING
INDICATOR OUTPUT
FROM POWER
HARNESS - (PURPLE) 7699
FRONT
AIR
HARNESS
600 SERIES
CONTROL BOX CONNECTION DIAGRAM
4-POINT AIR LEVELING
BATTERY - (RED) 6100
IGNITION - (YELLOW) 6110
ACCESSORY - (BROWN) 6120
COMPRESSOR FROM REAR
AIR HARNESS - (BLACK) 9700
LREAR RAISE - (GREEN) 4500
LR LOWER - (PURPLE) 4600
REAR AIR PRESS SW (YELLOW) 3215
REAR TRAVEL SOL. - (GRAY) 3700
RR LOWER - (BROWN) 3600
RR RAISE - (ORANGE) 3500
PRESSURE SW. INPUTS
FROM FRONT AIR HARNESS
RF AIR PRESS SW (ORANGE) 2210
LF AIR PRESS SW - (BLACK) 1210
AIR LEVELING CONNECTIONS ONLY
ARE SHOWN. AN EXISTING CONTROL BOX
MAY HAVE CONNECTIONS FOR HYDRAULIC
LEVELING WHICH MAY OR MAY NOT BE USED.
NOTE: THE (4) DIGIT WIRE NUMBER
SUPERSEDES ANY AND ALL WIRE
COLORS.
GROUND
WIRES FROM
REAR AIR
HARNESS (2) 6258
FUSE DESIGNATION
1 RIGHT FRONT LOWER
2 RIGHT FRONT RAISE
3 BATTERY
4 IGNITION
5 RIGHT REAR LOWER
6 LEFT REAR LOWER
7 LEFT REAR RAISE
8 RIGHT REAR RAISE
9 LEFT FRONT RAISE
10 LEFT FRONT LOWER
11 TRAVEL
#10 WHITE WIRE
FROM POWER HARNESS (WHITE) 6230
GROUND WIRES
FROM FRONT
AIR HARNESS (2) 6254
MP85.4510
26MAR02
ELECTRICAL CONNECTION DIAGRAM
AIR COMPRESSOR
COMPRESSOR
HARNESS FROM
CONTROL BOX
+12 SIGNAL - (BLACK OR BROWN) 9700
(A)
NOTE: THE (4) DIGIT WIRE NUMBER
SUPERSEDES ANY AND ALL WIRE
COLORS.
PRESSURE SWITCH (D)
OPEN 115 PSI
CLOSE 105 PSI
6
WHITE
GROUND
5
BROWN +12 (F)
3
4
ORANGE
12 VOLT
ESSEX
RELAY
(C)
7
BLACK ( GROUND )
RELAY MTG. BOLT
RED +12
1
2
COMPRESSOR MOTOR
(E)
FUSE
15 AMP
(B)
GRAY (GROUND)
15 AMP
GRAY (+12 SIGNAL)
(RED) 6100
NORMALLY OPEN
12 VOLT AIR SOLENOID
+12 VOLT
BATTERY POWER
MP85.4525
14FEB02
ELECTRICAL CONNECTION FOR
AIR LEVELING SYSTEM
WITH TOUCH PANEL CONTROL
TO AUX. AIR
COMPRESSOR SEE
AIR COMPRESSOR
DIAGRAM - (BLACK) 9700
SEE CONTROL
BOX DIAGRAM
TOUCH PANEL
MODULAR
CABLE
COMPUTERIZED LEVELING
HYD
AIR
EXCESS
SLOPE
LEVEL
NOT IN
PARK/
BRAKE
STORE
TO BRAKE LIGHT
ON DASH - 9001
GROUND
STUD
DUMP
TRAVEL
OFF
RAISE
CAUTION!
UNDERSTAND OPERATOR’S MANUAL BEFORE USING. BLOCK FRAME AND TIRES
SECURELY BEFORE REMOVING TIRES OR CRAWLING UNDER VEHICLE.
PARK BRAKE
SWITCH
(WHITE) 6258
(WHITE) 6254
PARK
BRAKE (BLUE)
9000
(WHITE)
6230
POWER
HARNESS
(PURPLE) 7699
TO MASTER
WARNING
INDICATOR
SENSING
UNIT SYSTEM
GROUND (WHITE)
6230
FRONT AIR
MANIFOLD
HARNESS
IGNITION (YELLOW) 6110
BATTERY (RED) 6100
ACC.
(BROWN) 6120
TRAVEL (GRAY) 1700
PRESSURE SW.
LF AIR (BLACK) 1210
TRAVEL - (GRAY) 1700
PRESSURE SW. RF AIR (ORANGE) 2210
LF LOWER (RED) 1600
RF LOWER - (BLUE) 2600
RF RAISE - (YELLOW) 2500
LF RAISE (GREEN) 1500
REAR AIR MANIFOLD
SEE AIR SOLENOID
MANIFOLD DIAGRAM
W/2 PRESSURE SWITCH
NOTE: THE (4) DIGIT WIRE NUMBER
SUPERSEDES ANY AND ALL WIRE
COLORS.
TRAVEL (GRAY) 3700
TRAVEL - (GRAY) 3700
PRESSURE SW. (YELLOW) 3215
RR LOWER (BROWN) 3600
LR LOWER (PURPLE) 4600
LR RAISE (GREEN) 4500
RR RAISE (ORANGE) 3500
SEE AIR SOLENOID
MANIFOLD DIAGRAM
W/1 PRESSURE SWITCH
MP85.453F
03FEB99
MOUNTING AND ADJUSTMENT INSTRUCTIONS
LEVEL SENSING UNIT
The sensing unit must be mounted to a solid surface and must not be exposed to any heat sources. Toward the middle of the
vehicle but outside the frame rails is best. The sensing unit may be mounted between frame rails on pusher vehicles and trailers.
The sensing unit may be mounted in a compartment but needs to be protected from stored objects. It is critical that the sensing
unit is mounted in the proper position according to the sticker on the sensing unit. (See figure below). The springs should be compressed to approximately 1.25 inches.
The correct method for adjusting the sensor is as follows:
First, level the vehicle by placing a 24" level in the center of the vehicle on the floor. With the vehicle level adjust the sensing unit
until all yellow lights are out. This is done by drawingup or backing out the sensing unit screws. If a front light is on, adjust the
front screw. If a side light is on adjust the side screw. If a rear light is on adjust the rear screws. One or more screws may have
to be adjusted to turn the yellow lights out. After adjustment has been made, pull down on the sensing unit to make sure the unit
is bottomed out on the screw heads. Check to make sure all yellow lights are out. If not, readjust. Rock the vehicle and recheck for yellow lights, readjust if needed.
NOTE: The sensing unit has an accuracy tolerance of +/- 1" side to side and +/- 5.4" front to rear on a 36’ vehicle.
SOLID MOUNTING SURFACE
SPRINGS (3)
SENSING UNIT
4" DIA. X 3/4" THICK
SCREWS (3)
REAR
CROSS MTG (BI-AXIS) SENSING UNIT
THIS
SIDE
UP
MP85.9505
01JUL98
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