HWH 725 SERIES Service Manual Download

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SERVICE MANUAL

ML48380/MI91.0030

19MAR12

Single Step Touch Panel Leveling Control

BI-AXIS Hydraulic Leveling

FEATURING:

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

725 SERIES HYDRAULIC LEVELING SYSTEM

HWH TOUCH PANEL-CONTROLLED

(Without Dump)

(With Dump)

(With Pilot Dump)

CORPORATION

Straight-Acting Jacks

UNDERSTAND OPERATOR’S MANUAL BEFORE USING. BLOCK FRAME AND TIRES

SECURELY BEFORE REMOVING TIRES OR CRAWLING UNDER VEHICLE.

HWH COMPUTERIZED LEVELING

EXTEND

RETRACT

WARNING!

DUMP

MANUAL

CANCEL

LEVEL

AUTO

STORE

AUTO

PARK/

NOT IN

MODE

BRAKE

TRAVEL

SLOPE

EXCESS

MANUAL

RETRACT

EXTEND

Summary of Contents for 725 SERIES

Page 1: ...08 www hwh com 725 SERIES HYDRAULIC LEVELING SYSTEM HWH TOUCH PANEL CONTROLLED R Without Dump R With Dump With Pilot Dump W CORPORATION H H R Straight Acting Jacks UNDERSTAND OPERATOR S MANUAL BEFORE USING BLOCK FRAME AND TIRES SECURELY BEFORE REMOVING TIRES OR CRAWLING UNDER VEHICLE HWH COMPUTERIZED LEVELING EXTEND RETRACT WARNING DUMP MANUAL CANCEL LEVEL AUTO STORE AUTO PARK NOT IN MODE BRAKE TR...

Page 2: ...ATION AND GLOSSARY OPERATION SYSTEM This manual is written in two sections Section 1 is System Operation and Trouble Shooting Steps Section 2 is the Diagrams and Parts Glossary Begin diagnosis of the system with Section 1 This will give the correct operation and function of the system The Trouble Shooting Steps are written in order of operation The Trouble Shooting Steps should be followed in orde...

Page 3: ...ce the I O module or touch panel unless the Repair Steps say to replace it Otherwise the malfunctions may damage the new I O module or touch panel 5 Proper grounding of all components is critical See the electrical circuit for specific grounds required Faulty grounds especially for the I O module touch panel solenoid manifold or the pump assembly may cause component damage and or improper or errat...

Page 4: ...tion is in the ON extended 1 4 to 1 2 inch start the automatic leveling function It will sound if the master JACKS DOWN CONTROL IDENTIFICATION 725 SERIES LEVELING SYSTEM COMPUTER CONTROL or ACC position the system is on and the jacks are It will be on when any one or more jacks are extended button is being pushed RETRACT EXTEND HWH COMPUTERIZED LEVELING SECURELY BEFORE REMOVING TIRES OR CRAWLING U...

Page 5: ... to the level lights starting with a lit side light When all four level lights are out the computer will extend any jacks not used for leveling to stabilize the vehicle There are two parts to leveling a vehicle First the vehicle is leveled The jacks are used to turn all the yellow level indicators off The second part of leveling is to stabilize the vehicle This is accomplished by extending any jac...

Page 6: ...ing the AUTO LEVEL button again or pushing the STORE button will stop the automatic leveling process If the vehicle is equipped with remote leveling system rocker switches pushing the rocker switch to LEVEL or STORE will stop the automatic leveling process STORE button EXCESS SLOPE AUTOMATIC OPERATIONS CONTINUED STABILIZING Each jack has a pressure switch When the jack pressure switch is on the co...

Page 7: ...t on the touch panel on The IMPORTANT When testing a leveling system all four sets of UP and DOWN arrow buttons should be used to make sure the complete system operates correctly including the red WARNING lights and the yellow LEVEL lights If the system will not work in the manual mode it is very unlikely the system will function properly in the automatic mode is equipped with an air suspension th...

Page 8: ...ctor If there is proper resistance of 60 ohms 10 and green wires are properly seated into the 32 pin and 5 pin connectors If the wires and or the touch panel There is no good test to determine which is bad The touch panel would SEE MP84 3334 Note If the ohm meter shows improper resistance unplug the touch panel and check pins 1 SEE MP84 3170 and 2 of the harness connector If the resistance is now ...

Page 9: ...uch panel lights are on push the STORE button The STORE light should start to flash 1 The STORE light starts to flash or any other touch panel light comes on Replace the touch panel 2 The STORE light does not flash and no touch panel light comes on There may be no power or ground to the touch panel Check the link light on the back of the touch panel If the link light is on or blinking replace the ...

Page 10: ...in the harness to the touch panel or at one of check the white 14 gauge ground wire coming from the top of the SEE MP84 3240 unplug the 32 pin connector at the I O module If there is a ground on pin B3 If there is no ground on pin B3 I O module are ok replace the I O module If there is no power on pin 5 at the touch panel blinking there is power on pin D1 in the harness plug MANUAL OPERATION 725 T...

Page 11: ... no continuity to ground check and record the voltage between pin D1 of the 32 pin harness connector and the brass ground stud on the top of the I O module Plug the 32 pin connector back in Check the voltage between the ground and signal wire in the warning switch plug The voltage should be within less than 1 volt of the voltage you recorded on pin D1 of the harness connector If the voltage is goo...

Page 12: ...CAUSING INJURY OR DEATH CHOCK THE VEHICLE WHEELS BEFORE RELEASING THE PARK BRAKE It is also important that the park brake circuit is functioning properly and that the system The system will not function if the park brake is not set SEE MP84 3170 Reset the park brake on the touch panel arrow ground WARNING cannot function with the park brake released PART 5 PARK BRAKE CHECK MANUAL OPERATION 725 TRO...

Page 13: ...rn to ride height if there is ample air in the suspension air tanks If both link lights are flashing the next step is checking voltage check voltage between the white and red wire in the 5 pin MTA connector on the back of voltage to the I O module should be checked Ign Acc voltage to the I O module is on pin D1 in the 32 pin connector at the I O module Ground for the I O module and touch panel is ...

Page 14: ... STEP LEVELING SYSTEM ELECTRICAL CONNECTION DIAGRAM FUSE 15 AMP MANUAL HWH COMPUTERIZED LEVELING SECURELY BEFORE REMOVING TIRES OR CRAWLING UNDER VEHICLE UNDERSTAND OPERATOR S MANUAL BEFORE USING BLOCK FRAME AND TIRES TOUCH PANEL 7699 7699 PARK BRAKE DIODE NOTE DIODE ARRANGEMENT MAY NOT BE PRESENT ON ALL INSTALLATIONS LR BY O E M CONNECTION PILOT DUMP SWITCH PRESSURE SWITCH 4200 SWITCH WARNING 400...

Page 15: ...ere is a short to ground on the 9301 travel wire in the harness between find the 4 pin UML plug and unplug it Plug the 3 pin Packard connector back in Check the travel LED pushing the STORE button If the LED is still off replace the I O module If the travel LED is now on 10 15 seconds and plug the 32 pin connector back in Turn the ignition on Check the travel LED after module Turn the ignition off...

Page 16: ...e 10 volt or more at the 4 pin UML connector with the connector plugged in the problem is with the suspension dump equipment contact the vehicle manufacturer If there is no voltage at the 4 pin UML connector the problem is with the connections or harness wires between the 3 pin Packard connector and the 4 pin UML connector SEE MP84 3135 and MP84 3170 SEE MP843135 Start the vehicle engine and make ...

Page 17: ...0 SEE MP84 3130 IS BEING PUSHED PARK BRAKE LIGHT IS NOT COMING ON 1 The red master relay LED is NOT on the master relay coil may have a short to ground B A circuit PUSH AND HOLD AN UP ARROW PUSH AND HOLD THE CORRESPONDING DOWN ARROW SEE MP84 3170 SEE MP84 3170 The jacks should retract fully and the jack MANUAL SYSTEM OPERATION 725 TROUBLE SHOOTING STEPS PART 7a EXTENDING JACKS WITH UP ARROW BUTTON...

Page 18: ...eck terminal 3 low voltage could be an issue and terminal connection to the relay relay LED on replace the I O module under load If terminal 3 has power SEE MP84 3240 SEE MP84 3240 If there is no voltage on terminal 1 12 battery SEE MP84 3240 SEE MP84 3240 If terminal 3 has no power MANUAL SYSTEM OPERATION 725 TROUBLE SHOOTING STEPS the master relay MULTIPLEX I O MODULE DEUTSCH CONNECTOR SEE DETAI...

Page 19: ...ONS VALVES MAY PROCEDURE FOR MANUAL JACK RETRACTION VALVE RELEASE READ AND UNDERSTAND BEFORE OPERATING MANUAL valve tube REAR LEFT WITH VELOCITY ARE EQUIPPED MANIFOLDS NOTE SOME SWITCH PRESSURE 3000PSI HERE VALVES LR LF shuttle valve and shuttle to be removed to access may need to be removed not shown load center NOTE Load center is FRONT LEFT NOTE WITH RELEASE SMALL VALVES LARGE AND RELEASE CAMS ...

Page 20: ...ressure solenoid valve or the inner check valve for that jack Contact HWH Corporation for assistance reconnect the hose to the manifold and remove the hose at the jack There should be a good flow of fluid to the jack when pushing the UP arrow If there is no flow the hose is the problem If there is good flow replace the jack cylinder MP64 3917 MP84 3170 LEFT FRONT JACK LEFT REAR JACK LINK LIGHT MAS...

Page 21: ...SENT BUT NOT ALWAYS USED 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 shuttle valve and shuttle CHECK PRESSURE WITH VELOCITY ARE EQUIPPED MAN...

Page 22: ...and the buzzer have specific and polarity remains reinstall the original touch panel and replace the I O module L SEE MP84 3334 and MP84 9964 SEE MP84 3170 PART 7a SECTION K CONTINUED MANUAL SYSTEM OPERATION 725 TROUBLE SHOOTING STEPS TOUCH PANEL LINK LIGHT ON SOLID OR OFF INDICATES COMMUNICATION BETWEEN THE I O MODULE AND THE LINK LIGHT LINK LIGHT FLASHING INDICATES PROPER 12 VOLTS ON THE CORRESP...

Page 23: ...the master relay If there is low voltage to the master relay the problem is the battery cable cable connections at the battery or master relay or there is battery issues and corrosion SEE MP64 3917 and MP84 3240 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...

Page 24: ...170 MP84 3170 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 SWITCHED GROUND FROM RIGHT FRONT JACK WARNING SWITCH SWITCHED GROUND FROM R...

Page 25: ...at the jack If the jack retracts normally the hose is restricted or kinked If the jack still retracts slowly or not at all replace the jack cylinder two pins replace the warning switch MP84 3170 RIGHT REAR JACK RIGHT FRONT JACK ELECTRICAL CONNECTION DIAGRAM MULTIPLEXED INPUT OUTPUT MODULE LED AND WIRE CONNECTION INFORMATION LEFT FRONT JACK LEFT REAR JACK A LIT RED LED INDICATES THERE SHOULD BE 12 ...

Page 26: ...nplug the 32 pin connector from the I O module With both ends unplugged the wires for pins 1 4 5 and 6 of the sensing unit plug should have continuity from end to end and should not be shorted to any other wire in the harness or to a frame ground Fix the harness as necessary If the harness is good replace the I O module SEE MP84 3170 for sensing unit wire pin out information at the 32 pin harness ...

Page 27: ...es into the stabilize mode While in the stabilization mode yellow level lights may come back on 725 TROUBLE SHOOTING STEPS MANUAL SYSTEM OPERATION AUTOMATIC LEVELING AUTOMATIC LEVELING SEQUENCE MP84 3170 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...

Page 28: ...the jack pressure switches are in Note During the stabilize mode the pump only runs if a jack needs to be extended The pump will most likely turn on and off several times while checking the jack pressure switches and yellow level lights during the STABILIZE MODE 8 When the system has completed the stabilize mode the system will shut off The red warning lights will remain on until the ignition is t...

Page 29: ... BRAKE SWITCH SWITCHED GROUND FROM SENSING UNIT FRONT SWITCHED GROUND FROM SENSING UNIT LEFT SIDE SWITCHED GROUND FROM LEFT FRONT JACK PRESSURE SWITCH SWITCHED GROUND FROM LEFT FRONT JACK WARNING SWITCH GROUND FOR JACK WARNING SWITCHES 12 VOLT ACCESSORY POWER FOR I O MODULE SWITCHED GROUND FROM SENSING UNIT RIGHT SIDE SWITCHED GROUND FROM LEFT REAR JACK WARNING SWITCH SWITCHED GROUND FROM SENSING ...

Page 30: ...R 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 M...

Page 31: ...ts remain on the system will stay in the STORE mode for fifty 50 minutes from the time the STORE button was pushed The TRAVEL MODE light will not be on Any lit red warning lights will remain on After fifty 50 minutes the store indicator light will go out The TRAVEL MODE light will remain off Any red warning lights that were on will stay on AUTOMATIC STORE DIAGNOSTICS PART 12 DIAGNOSTICS FOR THE AU...

Page 32: ...ING THE SENSING UNIT AFTER ADJUSTING THE SENSING UNIT BUMP THE SENSING UNIT TO SEE THAT IT IS SETTLED TIGHT AGAINST ALL THREE SCREW HEADS AND STILL INDICATES THAT THE UNIT IS LEVEL Level the vehicle by placing a bubble level in the center of the freezer floor or upon whichever surface within the vehicle that is to be level It is best if the level is placed close to the mounting area of the sensing...

Page 33: ...R CAP VELOCITY VALVE NOTE SOME MANIFOLDS ARE EQUIPPED WITH VELOCITY VALVES LF RF 3000PSI PRESSURE SWITCH 50PSI PRESSURE SWITCH RR LR MANIFOLDS MAY HAVE FOUR 4 LARGE VALVES OR FOUR 4 SMALL VALVES BE EQUIPPED WITH VALVE RELEASE NUTS OR RELEASE CAMS LARGE AND SMALL VALVES WITH RELEASE NUTS LARGE AND SMALL VALVES WITH RELEASE CAMS PRESSURE 3000 PSI ALTERNATE SWITCH LOCATION NOTE Load center is not sho...

Page 34: ...ESSURE SWITCH JACK CYLINDER LEFT REAR RIGHT REAR RIGHT FRONT LEFT FRONT MP64 4530 29MAR10 3000 PSI SWITCH LEVELING SYSTEM ROOM EXTENSION MANIFOLD LOCATED HERE WHEN APPLICABLE RR SOL VALVE USED ON AUTOMATIC SYSTEMS ONLY NOTE 50 PSI PRESSURE SWITCH MAY NOT BE USED ON ALL 625 MANIFOLDS 3500 P S I BI AXIS LEVELING WITH STRAIGHT ACTING JACKS 625 625S OR 725 SERIES HYDRAULIC SCHEMATIC DIAGRAM 800 PSI TO...

Page 35: ...ief valve set screw clockwise until the pressure gauge shows a minimum of 3300psi www hwh com http www hwh com The sheet is located under Customer Support Technical Service Note Instruction sheet MI95 74 explains how to run the pump using jumper wires This sheet is available at MANUAL side of the leveling system touch panel If the touch panel is used the ignition must be in the ACC position and 3 ...

Page 36: ...RETRACT EXTEND SEE ELECTRICAL CONNECTION DIAGRAM LEVELING SYSTEM HYDRAULIC MANIFOLD PUMP AND MASTER RELAYS SEE ELECTRICAL CONNECTION DIAGRAM SENSING UNIT DO NOT CUT TERMINATING RESISTOR DO NOT CUT TERMINATING RESISTOR MULTIPLEXED INPUT OUTPUT MODULE SEE ELECTRICAL CONNECTION DIAGRAM 8100 8101 FUSE 15 AMP LIGHT WARNING MASTER 12V IGNITION CONNECT TO _ BUZZER FUSE 5AMP 7699 7699 PARK BRAKE SWITCH DI...

Page 37: ...ING SYSTEM HYDRAULIC MANIFOLD W PILOT AIR DUMP SEE ELECTRICAL CONNECTION DIAGRAM SENSING UNIT C A B PILOT AIR DUMP DO NOT CUT TERMINATING RESISTOR DO NOT CUT TERMINATING RESISTOR MULTIPLEXED INPUT OUTPUT MODULE SEE ELECTRICAL CONNECTION DIAGRAM 6230 9300 9301 8100 8101 6230 GND 9301 TRAVEL 9300 DUMP PILOT DUMP CONNECTION BY O E M CONNECTION 7699 7699 PRESENT ON ALL INSTALLATIONS NOTE DIODE ARRANGE...

Page 38: ...UNIT C1 RED 6121 SHIELD WIRE FOR GREEN YELLOW CAN COMMUNICATION WIRES N A C2 N A GROUND FOR LEVEL SENSING UNIT WHITE C3 6231 SWITCHED GROUND FROM SENSING UNIT REAR 0400 BLACK C4 SWITCHED GROUND FROM LEFT REAR JACK WARNING SWITCH 4000 BLACK C5 NO CONNECTION C6 AND C7 SWITCHED GROUND FROM SENSING UNIT RIGHT SIDE 0300 BLACK C8 D1 RED 6120 12 VOLT ACCESSORY POWER FOR I O MODULE GROUND FOR JACK WARNING...

Page 39: ...AY A 40 AMP FUSE SWITCH 8100 SEE DETAIL A MULTIPLEX I O MODULE 50 LB PRESSURE SWITCH 8101 6230 RELAY GND 6800 DEUTSCH CONNECTOR 12 VOLT BATTERY TO GROUND STUD ON PUMP 6230 POWER UNIT SIDE VIEW GROUND STUD I O MODULE SEE DETAIL A MULTIPLEX SYSTEM SINGLE STEP LEVELING DIAGRAM 725 SERIES SEE ELECTRICAL CONNECTION LR A B RR LF RF B A A B B A 6230 6230 4400 6230 2400 1400 6230 3400 DETAIL A TOP VIEW MU...

Page 40: ...CH 8100 SEE ELECTRICAL CONNECTION DIAGRAM 725 SERIES SINGLE STEP LEVELING SYSTEM PILOT AIR DUMP GND 6231 DUMP 9300 TRAVEL 9301 SEE DETAIL A MULTIPLEX I O MODULE 50 LB PRESSURE SWITCH 4400 1400 2400 3400 8101 6800 DEUTSCH CONNECTOR TO GROUND STUD ON PUMP 6230 POWER UNIT SIDE VIEW GROUND STUD I O MODULE SEE DETAIL A MULTIPLEX A B B A A B B A 6230 6230 6230 6230 RR RF LF LR TOUCH PANEL HARNESS 6230 R...

Page 41: ...TRACT AUTO STORE LEVEL AUTO WARNING BRAKE TRAVEL CANCEL MODE PARK NOT IN EXCESS R SLOPE MANUAL RETRACT EXTEND MANUAL DUMP YELLOW GREEN WIRE COLOR WHITE 5 PIN MTA CONNECTOR 3 4 5 RED PIN 2 1 6800 6230 NUMBER WIRE 12 VOLTS FROM INPUT OUTPUT MODULE CAN SHIELD GROUND FROM CONTROL BOX WIRE DESCRIPTION AND FUNCTION CAN LOW CAN HIGH MP84 3334 PIN 4 PIN 1 6 5 NO CONNECTION 6 PIN UML CONNECTOR 1 THRU 4 SWI...

Page 42: ... C YELLOW LEDS BOTTOM VIEW OF SENSING UNIT LED A FRONT OF VEHICLE LED B LEFT SIDE OF VEHICLE DRIVER SIDE LED C REAR OF VEHICLE LED D RIGHT SIDE OF VEHICLE PASSENGER SIDE WIRE LEGEND PIN 1 BLACK 0400 SWITCHED GROUND WHEN REAR IS LOW PIN 2 WHITE 6231 GROUND FROM SENSING UNIT PIN 3 RED 6121 12 VOLT FOR SENSING UNIT PIN 4 BLACK 0100 SWITCHED GROUND WHEN LEFT SIDE IS LOW PIN 5 BLACK 0200 SWITCHED GROUN...

Page 43: ... B1 15 AMP FUSE 6120 PIN 5 PIN 4 5 PIN MTA CONNECTOR 12 ACC RED 6800 GROUND WHITE 6230 BATTERY 12 VOLT I O MODULE PIN D1 THE ABOVE RESISTANCE POINTS ARE IMPORTANT TO REMEMBER WHEN CHECKING VOLTAGE A LOSE PIN CONNECTION CORRODED WIRE OR BAD RING TERMINAL CONNECTION CAN CAUSE LOW VOLTAGE BECAUSE OF A LOOSE CONNECTION OR CORROSION THE VOLTAGE ON A RELAY TERMINAL MAY BE DIFFERENT THAN THE VOLTAGE ON T...

Page 44: ...se pliers to turn the adjustment body If a jack needs to lift a little more for stabilizing turn the adjustment body clockwise This will increase the pressure If a jack is lifting too high turn the adjustment body counterclockwise This will decrease the pressure Only turn the adjustment body a half a turn at a time then check the operation of the system Remember to plug the switch in for the test ...

Page 45: ...T ACTING JACKS A WARNING BUZZER MUST BE USED NOTE BY SUPPLYING IGNITION POWER TO THE WARNING BUZZER AND LIGHT AND ACC POWER TO THE TOUCH PANEL THE SYSTEM MAY BE OPERATED IN ACCESSORY WITHOUT THE BUZZER SOUNDING THE NEGATIVE SIGNAL FOR THE WARNING INDICATORS MUST ALWAYS COME FROM THE TOUCH PANEL PIGTAIL W DIODE AND IN LINE FUSE HOLDER 6121 PIGTAIL PROVIDED 7699 IGNITION 6111 7699 6111 7699 7699 WAR...

Page 46: ... a small style 12 volt valve Replace considered when replacing any HWH hydraulic solenoid valve Replace a small style 12 volt Valve size and voltage are still factors to be replacements for all previous styles of The cam release style valves are direct HWH hydraulic solenoid valves 12 volt valve This is true for 24 volt valves also turn out the old valve confirm that no o ring stress on the wires ...

Page 47: ...ags When the dump valves are open they exhaust all the air from the air bags and the vehicle suspension Normally the complete harness for this system is supplied by HWH There are two wires to each valve a white wire and a black number 9300 wire The HWH I O module switches 12 volts to open the air dump valves each solenoid valve The check valves allow two solenoid valves to be opened at the same ti...

Page 48: ...jacks are completely retracted with the STORE button or the park brake is released with the ignition on PRESSURE SWITCH JACK This pressure switch is a single wire normally open switch There is one mounted on each jack The contacts of this switch close when the pressure the switch is set at is reached The contacts of this switch when closed supply a ground signal to the I O module Smaller jacks and...

Page 49: ...ow ground If the ground is missing both small posts will show 12 volts The master relay will be on whenever the ignition is on and the park brake is set or while a room control switch is being pushed to EXTEND or RETRACT with the park brake set RELAY PUMP The pump relay is an intermittent duty normally open four post relay that consists of one pair of contacts and a coil The contacts are used to s...

Page 50: ...ire carries a ground signal to the I O module when the jack is in the vertical position and the steel ball is shorting the contacts together The I O module then turns on the appropriate red WARNING light on the touch panel When the jack is in the horizontal position the ball rolls away form the contacts opening the circuit This turns the red WARNING lights off B A There are two different SOLENOID ...

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