2007-2009 Workhorse W62 Chassis Service & Repair Manual

WORKHORSE CUSTOM CHASSIS Service Manual 2007 W62 Chassis WSM0419 SECTION 8 PAGE 2 Electrical Systems 2007 W62 Chassis TOC © 2006 Workhorse Custom Chassis — All Rights Reserved TABLE OF CONTENTS DESCRIPTION AND OPERATION.................................... 5 Diagnostic Link Connector Description........................ 5 16-Pin DLC .................................................................. 5 9-Pin DLC .................................................................... 5 Lighting Systems Description ...................................... 5 Headlamps .................................................................. 5 Daytime Running Lamps ............................................. 6 Flash-To-Pass.............................................................. 6 Park Lamps ................................................................. 6 Turn Lamps ................................................................. 6 Hazard Lamps ............................................................. 6 Stoplamps.................................................................... 6 Backup Lamps ............................................................. 6 Windshield Wiper/Washer System Description ........... 6 LOW or MIST Position ................................................. 7 HIGH Position .............................................................. 7 DELAY Operation ........................................................ 7 Washer Pump .............................................................. 7 Horns Description ........................................................ 8 Cruise Control System Description.............................. 8 Wiring Systems Description......................................... 8 Schematic Information ................................................. 8 CIRCUIT PROTECTION ........................................... 11 Fuses ......................................................................... 11 Circuit Breakers ......................................................... 12 Fusible Links.............................................................. 13 Wiring Repairs ........................................................... 14 Repairing Damaged Wire Insulation .......................... 14 Wiring Harness Replacement .................................... 14 Heated Oxygen Sensor (HO2S) Wiring Repairs ....... 14 Diagnosis Using The Wiring Schematics................... 14 Schematic Icons ........................................................ 14 Connector Reference Zone Numbers........................ 14 Underhood Fuse Panel.............................................. 15 Instrument Cluster Description and Operation .......... 15 Test at Turn On .......................................................... 22 Access to Diagnostic Menus and Menu Operation.... 22 Menu Operation ......................................................... 22 Adjusting Display Contrast ........................................ 23 Restore Default.......................................................... 23 Gauge Backlight ........................................................ 24 Software version ........................................................ 24 Part Number .............................................................. 24 Engine hours ............................................................. 24 Max Engine RPM....................................................... 24 Max Vehicle Speed .................................................... 24 Engine Oil Life Remaining ......................................... 25 DIAGNOSTIC INFORMATION AND PROCEDURES ..... 26 General Electrical Diagnosis Procedures .................. 26 Basic Knowledge Required ....................................... 26 Electromotive Force................................................... 26 Voltage....................................................................... 26 Resistance ................................................................. 27 Ohms ......................................................................... 27 Tips for Using an Ohmmeter ..................................... 27 Ohm’s Law................................................................. 28 Electrical Current ....................................................... 30 Amperage .................................................................. 30 Ammeter .................................................................... 30 The Diagnostic Process............................................. 31 General Electrical Diagnosis ..................................... 33 Troubleshooting with a Digital Multimeter (DMM) ...... 33 Measuring Voltage ..................................................... 34 Measuring Voltage Drop ............................................ 35 Measuring Frequency ................................................ 36 TOC

WORKHORSE CUSTOM CHASSIS Service Manual 2007 W62 Chassis WSM0419 SECTION 8 PAGE 3 Electrical Systems 2007 W62 Chassis TOC © 2006 Workhorse Custom Chassis — All Rights Reserved Testing for Continuity ................................................. 36 Testing for Short to Ground ....................................... 37 Testing for a Short to Voltage .................................... 38 Troubleshooting with a Short Finder .......................... 39 Troubleshooting with a Test Lamp ............................. 39 Probing Electrical Connectors ................................... 39 Using Connector Test Adapters ................................. 40 Using Fused Jumper Wires ....................................... 40 Using Connector Test Adapters ................................. 40 Intermittents and Poor Connections .......................... 41 Testing for Intermittent Conditions and Poor Connections............................................................ 41 Testing for Proper Terminal Contact .......................... 42 Testing for Proper Terminal Contact in Bussed Electrical Centers (BEC)......................................... 42 Flat Wire (Dock and Lock) Connectors...................... 43 Control Module/Component Voltage and Grounds .... 43 Temperature Sensitivity ............................................. 44 Electromagnetic Interference (EMI) and Electrical Noise ...................................................................... 44 Inducing Intermittent Fault Conditions ....................... 45 Low Temperature Conditions ..................................... 46 Duplicating Failure Conditions ................................... 47 Testing for Electrical Intermittents.............................. 47 Diagnostic Link Connector Diagnostics ..................... 48 Data Link Communications System Check .............. 48 Scan Tool Does Not Communicate with Components ............................................................ 49 Scan Tool Does Not Communicate with PCM ........... 51 Scan Tool Does Not Communicate with TCM ........... 52 Lighting Systems ....................................................... 55 Courtesy or Dome Lamps Always On........................ 55 Courtesy or Dome Lamps Inoperative ....................... 56 Instrument Panel Lighting Issues .............................. 58 Windshield Wiper/Washer Diagnosis ........................ 59 Washer Always On .................................................... 59 Washers Inoperative .................................................. 60 Wipers Inoperative – All Modes ................................. 62 Wipers Delay Mode Inoperative ................................ 63 Wipers High Mode Inoperative .................................. 64 Wipers Low or Mist Modes Inoperative ..................... 65 Cruise Control Diagnostics ........................................ 67 Cruise Control System Check ................................... 67 Cruise Control Does Not Set or Accelerate ............... 68 Horns ......................................................................... 72 Horns Always On ....................................................... 72 Horns Inoperative ...................................................... 73 Adjustable Pedals Diagnosis ..................................... 76 DTC U1001-U1254 .................................................... 78 DTC U1300, U1301, or U1305 .................................. 82 Instrument Cluster Diagnostic Information ................ 83 Cluster Diagnostic ..................................................... 83 Gauge Test ................................................................ 83 Warning Lamps Test .................................................. 84 LCD Test .................................................................... 84 Backlighting Test ........................................................ 85 Speaker Test .............................................................. 85 Switch Inputs ............................................................. 86 Analog Inputs............................................................. 86 Frequency Inputs ....................................................... 87 Troubleshooting the Instrument Cluster .................... 87 Gauges ...................................................................... 87 Warning lights ............................................................ 89 Backlighting ............................................................... 91 Misc. .......................................................................... 92

WORKHORSE CUSTOM CHASSIS Service Manual 2007 W62 Chassis WSM0419 SECTION 8 PAGE 4 Electrical Systems 2007 W62 Chassis TOC © 2006 Workhorse Custom Chassis — All Rights Reserved REPAIR INSTRUCTIONS ................................................ 98 Wiring Repairs ........................................................... 98 Repairing Damaged Wire Insulation .......................... 98 Splicing Copper Wire ................................................. 98 Splicing Twisted Pair Wiring .................................... 102 HO2S Wiring Repairs .............................................. 103 Headlamp Switch Replacement .............................. 103

WORKHORSE CUSTOM CHASSIS Service Manual 2007 W62 Chassis WSM0419 SECTION 8 PAGE 5 Electrical Systems 2007 W62 Chassis TOC © 2006 Workhorse Custom Chassis — All Rights Reserved 9-Pin DLC The 9-pin Diagnostic Link Connector (DLC) allows the technician to access the Allison Transmission Control Module (TCM) and/or the Electronic Control Unit (ECU) for the WABCO anti-lock brake system (ABS). 7 of the pins in the connector are used. The pin assignments are: • Pin A – chassis ground via ground terminal 12 • Pin B – Battery voltage to DLC • Pin C – J1939 Hi • Pin D – J1939 Lo • Pin E – J1939 Shield (ground) • Pin F – J1587 Hi • Pin G – J1587 Lo. LIGHTING SYSTEMS DESCRIPTION Headlamps The headlamps will turn on when the headlamp switch is placed in the ON position. When the low beam headlamps are on, the headlamps can be switched to the high beams by pulling the headlamp dimmer switch toward the driver until it clicks. When the headlamp dimmer switch is again pulled until it clicks, the headlamps will then switch to the low beams from the high beams. DESCRIPTION AND OPERATION DIAGNOSTIC LINK CONNECTOR DESCRIPTION All 2007 Model Year (2007MY) W62 chassis are equipped with two Diagnostic Link Connectors (DLC). The 16-pin DLC is used to connect a scan tool or laptop for the purpose of performing engine control system diagnostics. The 9-pin “Deutsch” DLC is used to connect a scan tool or laptop for the purpose of performing transmission and/or anti-lock brake system (ABS) diagnostics. 16-Pin DLC The 16-pin DLC is used to connect a scan tool for the purpose of performing engine control system diagnostics. Establishing communication allows the operator to monitor the systems for diagnostic purposes. Only 4 of the 16 pins are used. The pin assignments are: • Pin 2 – Class 2 Serial Data link to instrument cluster/ PCM/ECM • Pin 4 – Ground terminal 12 • Pin 5 – Ground terminal 37 • Pin 16 – Battery voltage feed to DLC.

WORKHORSE CUSTOM CHASSIS Service Manual 2007 W62 Chassis WSM0419 SECTION 8 PAGE 6 Electrical Systems 2007 W62 Chassis TOC © 2006 Workhorse Custom Chassis — All Rights Reserved Daytime Running Lamps The optional Daytime Running Lamps (DRL) illuminate the high beam headlamps at a reduced intensity. The DRL will operate when the ignition switch is in the RUN or START position and the gear selector lever is out of the PARK position. DRL is a programmable feature for vehicles sold in the United States. Turning on the headlamps will disable the DRL system. Flash-To-Pass When the headlamp dimmer switch is pulled toward driver, but does not click, the high beam headlamps will light for as long as the switch is held. This will occur in any headlamp state (off, DRL, low beams). Park Lamps The park lamps will turn on when the headlamp switch is placed in the PARK or ON position. Turn Lamps The turn lamps can only be activated with the ignition switch in RUN or START. When the turn signal switch is placed in a position to indicate a left turn or a right turn, the respective turn lamps will flash. The respective turn indicator will flash on the Instrument Panel Cluster (IPC). Hazard Lamps When the hazard switch is pressed, all turn lamps will flash. Both turn indicators will flash on the Instrument Panel Cluster (IPC). Stoplamps When the brake pedal is pressed, all stoplamps illuminate. Backup Lamps When the ignition switch is in RUN and the gear selector lever is in REVERSE, the backup lamps light. Instrument Cluster Dimming The instrument cluster lamps light when the park lamps are on. The brightness of the instrument cluster lamps is controlled by the instrument cluster dimmer switch located on the instrument panel. WINDSHIELD WIPER/WASHER SYSTEM DESCRIPTION Voltage is supplied to the wiper motor via the WIPER fuse when the ignition switch is in the ACC or RUN position. Different speeds and functions of the wiper motor are achieved by completing different ground paths through the wiper pulse control module. The windshield wiper relay feed coil is used to keep the wiper motor running. When the windshield wiper relay feed coil circuit is not grounded, the motor will not turn. Closing the various contacts in the wiper/washer switch will provide ground for this circuit and allow the motor to turn.

WORKHORSE CUSTOM CHASSIS Service Manual 2007 W62 Chassis WSM0419 SECTION 8 PAGE 7 Electrical Systems 2007 W62 Chassis TOC © 2006 Workhorse Custom Chassis — All Rights Reserved LOW or MIST Position With the wiper/washer switch in the LOW or MIST position: • Power is supplied to the Pulse Wiper Control Module via circuit 143 (YEL) • Ground is provided to the Pulse Wiper Control Module via circuit 150 (BLK) • Low signal is supplied by the Pulse Wiper Control Module to the body builder wiper system via circuit 97 (LT BLU) • Coil feed signal is supplied by the Pulse Wiper Control Module to the body builder wiper system via circuit 91 (GRA) • Multifunction switch signal is provided to the Pulse Wiper Control Module via circuit 112 (GRA) HIGH Position With the wiper/washer switch in the HIGH position: • Power is supplied to the Pulse Wiper Control Module via circuit 143 (YEL) • Ground is provided to the Pulse Wiper Control Module via circuit 150 (BLK) • Low signal is supplied by the Pulse Wiper Control Module to the body builder wiper system via circuit 97 (LT BLU) • Coil feed signal is supplied by the Pulse Wiper Control Module to the body builder wiper system via circuit 91 (GRA) • Multifunction switch signal is provided to the Pulse Wiper Control Module via circuit 112 (GRA) • High signal is supplied by the multifunction switch to the body builder wiper system via circuit 92 (PPL). DELAY Operation With the multifunction switch in one of the delay positions: • Power is supplied to the Pulse Wiper Control Module via circuit 143 (YEL) • Ground is provided to the Pulse Wiper Control Module via circuit 150 (BLK) • Coil feed signal is supplied by the Pulse Wiper Control Module to the body builder wiper system via circuit 91 (GRA) • Multifunction switch signal is provided to the Pulse Wiper Control Module via circuit 112 (GRA). Washer Pump When the contacts of the wash switch in the wiper washer switch close: • Power is supplied to the Pulse Wiper Control Module via circuit 143 (YEL) • Ground is provided to the Pulse Wiper Control Module via circuit 150 (BLK) • Low signal is supplied by the Pulse Wiper Control Module to the body builder wiper system via circuit 97 (LT BLU)

WORKHORSE CUSTOM CHASSIS Service Manual 2007 W62 Chassis WSM0419 SECTION 8 PAGE 8 Electrical Systems 2007 W62 Chassis TOC © 2006 Workhorse Custom Chassis — All Rights Reserved Depressing the SET and the R/A switches simultaneously will cancel the cruise control operation. Canceling the cruise control operation will not cancel the speed memory. WIRING SYSTEMS DESCRIPTION Schematic Information Where to Find Schematics The electrical schematics for the 2007 W-Series are not included in the service manual itself. Instead, the schematics reside on the Workhorse Dealers website (www.dealers.workhorse.com). Using the dealer’s user code and password, the technician can access the engineering drawings. Type the user code into the User Code ﬁeld and the password into the Password ﬁeld. DO NOT press the enter key. Use the mouse, and left click on the Campaigns and Service Information box in the center of the screen. • Coil feed signal is supplied by the Pulse Wiper Control Module to the body builder wiper system via circuit 91 (GRA) • Multifunction switch signal is provided to the Pulse Wiper Control Module via circuit 112 (GRA) • Output signal is supplied by the Pulse Wiper Control Module to the body builder wiper/washer system via circuit 94 (PNK). HORNS DESCRIPTION The HORN fuse applies voltage at all times to the horn relay. When the horn button is depressed, the contacts for the horn switch close to ground. The horn relay energizes and the contacts for the horn relay switch close. This supplies voltage directly to the right and left horns. Both horns are grounded through ground terminal 19. CRUISE CONTROL SYSTEM DESCRIPTION The cruise control system maintains the desired vehicle speed under normal driving conditions. The cruise control system has the following capabilities: CRUISE RESUME SPEED ACCELERATE COAST

WORKHORSE CUSTOM CHASSIS Service Manual 2007 W62 Chassis WSM0419 SECTION 8 PAGE 9 Electrical Systems 2007 W62 Chassis TOC © 2006 Workhorse Custom Chassis — All Rights Reserved After selecting the 2007MY link, a page will be displayed that shows all of the drawings available for the 2007MY. How to Use Schematics In the lower right corner of each page of the wiring diagram is a box containing information on the page’s contents. Note: As with other engineering documents a “sheet” contains information speciﬁc to a system or subsystem. Sheets may have more than one page. When the main menu screen appears, click on the Wiring Diagrams button. After clicking on the Wiring Diagrams button, the technician will be presented with a screen showing with several model year links. Clicking on the 2007 link, will result in the page with the links for all of the electrical schematics for the 2007 MY being displayed.

WORKHORSE CUSTOM CHASSIS Service Manual 2007 W62 Chassis WSM0419 SECTION 8 PAGE 10 Electrical Systems 2007 W62 Chassis TOC © 2006 Workhorse Custom Chassis — All Rights Reserved Navigation Box When a circuit continues elsewhere on the same page or on another page, a Navigation Box is shown to help you locate the continuation of the circuit. The top portion of the box gives you the details of the circuit. Below the line, the point where the circuit continues is shown along with the grid locator. Use the grid locator in the same way that a road map is used to pinpoint the location. Connector End Views Connector End Views show the cavity or terminal locations for all the related connectors shown in the system schematics. The drawings show the connector face as seen after the harness connector has been disconnected from a component or mating connector. Unused cavities are left blank in the table.

2007-2009 Workhorse W62 Chassis Service & Repair Manual

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