Volvo VNL User manual

Service Manual
Trucks
Group30
New Features
Electrical General
VNL, VNM
PV776-TSP23760/1

Foreword
Thedescriptionsandserviceprocedurescontainedinthismanualarebasedondesigns
andmethodsstudiescarriedoutuptoJanuary1996.
Theproductsareundercontinuousdevelopment.Vehiclesandcomponentsproduced
aftertheabovedatemaythereforehavedifferentspecificationsandrepairmethods.
Whenthisisbelievedtohaveasignificantbearingonthismanual,supplementaryservice
bulletinswillbeissuedtocoverthechanges.
Theneweditionofthismanualwillupdatethechanges.
Inserviceprocedureswherethetitleincorporatesanoperationnumber,thisisa
referencetoanS.R.T.(StandardRepairTime).
Serviceprocedureswhichdonotincludeanoperationnumberinthetitleareforgeneral
informationandnoreferenceismadetoanS.R.T.
Thefollowinglevelsofobservations,cautionsandwarningsareusedinthisService
Documentation:
Note:Indicatesaprocedure,practice,orconditionthatmustbefollowedinordertohave
thevehicleorcomponentfunctioninthemannerintended.
Caution:Indicatesanunsafepracticewheredamagetotheproductcouldoccur.
Warning:Indicatesanunsafepracticewherepersonalinjuryorseveredamagetothe
productcouldoccur.
Danger:Indicatesanunsafepracticewhereseriouspersonalinjuryordeathcouldoccur.
VolvoTrucksNorthAmerica,Inc.
Greensboro,NCUSA
Ordernumber:PV776-TSP23760/1
©1996VolvoTrucksNorthAmerica,Inc.,Greensboro,NCUSA
Allrightsreserved.Nopartofthispublicationmaybereproduced,storedin
retrievalsystem,ortransmittedinanyformsbyanymeans,electronic,me-
chanical,photocopying,recordingorotherwise,withoutthepriorwritten
permissionofVolvoTrucksNorthAmerica,Inc..

Contents
General........................................................................3
ElectricalSystem-VNL,VNM(06.96to02.98)........3
Specifications.............................................................5
ReplacementWireSizes............................................5
Tools............................................................................7
SpecialEquipment.....................................................7
DesignandFunction..................................................9
GeneralCircuitInformation........................................9
CircuitTypes............................................................11
StartingandChargingSystem.................................18
ElectricalPass-ThroughforCabWiring,Powerand
Ground.....................................................................22
SwitchesandControls.............................................23
FuseandRelayLocations.......................................29
LightingSystem........................................................35
Instrumentation.........................................................41
ServiceProcedures..................................................43
GeneralWorkPracticesandCautions....................43
Soldering/WireSplicing............................................46
BatteryCableFusibleLinkReplacement(Battery
toStarter).................................................................47
BatteryCableFusibleLinkReplacement(Ground
Cable).......................................................................48
IgnitionSwitchReplacement....................................50
IgnitionSwitchandHousingReplacement..............52
HornContactsReplacement....................................54
TurnSignal/CCSwitchReplacement......................56
WindshieldWiperSwitchReplacement...................58
Headlight/ParkingLampSwitchReplacement.........60
RoadLamp(FogLamp)SwitchReplacement........62
DimmerControl(dashillumination)Rheostat
SwitchReplacement................................................64
RearSuspensionCabUnloaderControlValve
Replacement............................................................66
LiftAxleControlValveReplacement.......................66
FifthWheelSliderValveReplacement....................66
DifferentialLockoutValveReplacement..................66
AxleLockControlValveReplacement....................66
DashAirSwitchReplacement.................................66
CigarLighterReplacement......................................68
HazardLampSwitchReplacement.........................69
AuxiliaryLightSwitchReplacement.........................69
Dash(LeftSide)SwitchReplacement.....................69
MarkerInterruptSwitchReplacement.....................70
IdleControlSwitchReplacement.............................70
HeatedMirrorSwitchReplacement.........................70
TractionControl(TCS)SwitchReplacement...........70
Dash(RightSide)SwitchReplacement..................71
RadioReplacement(DashMounted)......................72
IgnitionPowerRelayReplacement..........................74
AccessoryPowerRelayReplacement.....................76
DaytimeRunningLampControlModuleReplace-
ment.........................................................................79
CombiRelayReplacement......................................80
PowerWindowSwitchReplacement(RightorLeft)82
PowerMirrorSwitchReplacement..........................83
DigitalClock(Sleeper)Replacement.......................84
SleeperReadingLampSwitchReplacement..........86
SleeperHeaterControlSwitchReplacement..........86
SleeperControlPanelSwitchReplacement............86
WindshieldWiperMotorReplacement....................87
WindshieldWiperLinkageAssemblyReplacement88
OperationNumbers
1

2

Group 30 Electrical System—VNL, VNM General
General
Electrical System - VNL, VNM (06.96 to 02.98)
This manual describes the new electrical features of VN
Series vehicles from introduction 06.96 until 02.98, as well
as general heavy duty electrical service information. It
includes information on new components, circuit types,
controls, connectors and the tools commonly used for
maintenance.
The electrical systems of VOLVO trucks are designed
to withstand the demands of a heavy duty motor truck
under all types of operation. Every effort has been made
to provide trouble-free operation, easy maintenance and
service, and to provide maximum life of the system and
its components.
For more information on VNL and VNM electrical circuitry,
refer to the vehicle electrical schematics.
3

4

Group 30 Electrical System—VNL, VNM Specifications
Specifications
Replacement Wire Sizes
The size of wire used when installing accessories or re-
pairing existing electrical items is dependent on the length
of the wire and power requirements of the accessory. The
chart below can be used to determine the proper wire size
for 12 volt systems.
To use the chart, mark the appropriate length for the wire
being installed in the m/ft column. Also mark the rating in
the amps/watts column. Then draw a line connecting the
mark in the length column to the one in the rating column.
The point where the line crosses the wire size column is
the size of the wire required. If the line crosses the wire
size column between gauge sizes, round up to the next
larger size.
If replacing a wire and the amperage of the circuit is
not known, it can be measured using a digital multimeter
placed in series in the circuit.
EXAMPLE:
A 12 volt hydraulic pump motor is rated at 20 amps.
The complete length of the circuit (power and ground
sides) is approximately 20 feet.
A line drawn from 20 on the length column to 20 on the
rating column crosses the wire size column at the 8.
This indicates that the minimum wire size for the applica-
tion is 8 gauge.
W3001006
Chart for calculating relationship between wire
length, gauge and amperage/wattage
5

6

Group 30 Electrical System—VNL, VNM Tools
Tools
Special Equipment
The following items can be ordered from the vendors listed.
Digital Multimeter (DMM)
A Digital Multimeter (DMM) is one of the most important
tools available for electrical troubleshooting. A multimeter
such as a Fluke 87 is recommended for troubleshooting.
It provides diagnostic capabilities such as current (amper-
age), resistance and voltage tests, as well as specialized
features for automotive troubleshooting. Any circuit can
be tested for continuity or short circuits with a low-reading
voltmeter.
CAUTION
Never use the ohmmeter mode in a powered circuit, or
as a substitute for a voltmeter or ammeter, as damage
to the instrument will result. Use the ohmmeter mode
only when power is removed from the circuit.
When using a multimeter and the value being tested is
unknown, always use the highest scale first and work
down to a mid-scale reading whenever possible. This will
avoid damage to the instrument.
Before using the DMM to measure resistance, check its
calibration by touching the leads together. If there is a
reading other than zero, subtract it from measurements
made with the DMM.
The following tests can be performed with a DMM:
•Current (amperage) check
•Voltage check
•Resistance check
•Diode check
W2001014
Fluke 87 Digital Multimeter
Available from Volvo (P/N 9510060)
or available from your local Fluke dealer
Anti-Static Wrist Strap
A wrist grounding strap must be worn when working on
electronic equipment such as the instrument cluster. This
is to prevent electrostatic discharge (ESD), which can
damage electronic components. To use the wrist strap in
a vehicle, attach the alligator clip to the nearest electrical
ground such as a ground terminal or preferably a ground
stud.
W3000572
Anti-Static Wrist Strap
Available from Kent-Moore (P/N BT-8639-B)
Call 1-800-328-6657
7

Group 30 Electrical System—VNL, VNM Tools
Static Dissipative Mat
Make sure the workbench has an anti-static mat which
is grounded to the nearest electrical outlet when working
on electronic equipment such as the instrument cluster.
When working at the anti-static workbench, always keep
a wrist strap connected to the anti-static mat. Note that
the Static dissipative kit shown includes both an anti-static
mat and wrist strap.
W3000704
Full-Size Type 8501 Static-Dissipative Grounding
Kit, Available from Newark (P/N 46F7444)
Call 1–910–292–7240
Rheostat Removal Tool
The rheostat removal tool is used when removing the dash
rheostat (see
Service Procedures ).
W3000799
Rheostat Removal Tool
Available from Kent-Moore (P/N J-42395)
Call 1-800-328-6657
Window/Mirror Switch Removal Tool
The window/mirror switch removal tool is used to remove
the power window and motor/heated mirror switch con-
nectors (see
Service Procedures ).
W3000800
Window/Mirror Switch Removal Tool
Available from Kent-Moore (P/N J-42396)
Call 1-800-328-6657
8