Operation
CircuitBreakers,FusesandFusibleLinks
WARNING
Topreventpropertydamage,personalinjury,and
/ordeath,donotincreasesizeoffuseorcircuit
breakerorchangetypeofbreakersupplied
withyourtruck,asthiscouldcausewiringto
overheatandpossiblyburn.Electricalcircuits
aredesignedwithaparticularwiregaugetomeet
thefuseandcircuitbreakercurrentrating.
•Electricalcircuitsareprotectedbytheelectricalsystem
controller,circuitbreakers,fuses,orfusiblelinks.Forthe
sizeandlocationofcircuitbreakers,fusesandfusible
links,pleaserefertotheMaintenanceIntervalsand
Specicationssectionofthismanual.
•Fusiblelinksconsistofalengthoflightergaugewirein
acircuit.Incaseofashortoroverload,thefusiblelink
opens(burnsout)toprotecttheremainderofthecircuit.
Repairconsistsofinstallinganewfusiblelinkwiththe
samegaugewireastheopenedfusiblelink.
•Circuitbreakersinterruptthecircuitwhenanoverload
orshortoccurs.Manualcircuitbreakers(TypeIII)can
beresetbydepressingtheresetbuttononthebreaker.
HeadlampandwipercircuitsareprotectedbytheBody
Controller.TypeIIcircuitbreakerswillresetautomatically
iftheshortisremovedfromthecircuit.
•Thevariouselectricalunitsinthecabandengine
compartmentsareprotectedbyeitherfusesorcircuit
breakers.Thepowerdistributioncenterislocatedwithin
theinstrumentpanel(gloveboxarea)onthepassenger
sideofthevehicle.
ElectricalLoadControlandShedding(ELCS)
ElectricalLoadControlandShedding(ELCS)isanoptional
feature(standardwithsleepers)intendedtoprovidea
convenientmeansofautomaticallyshuttingdownelectrical
loadsovernightinordertoconserveenergyanddeliversufcient
powertostarttheengine.Thesystemisactivewhentheengine
isnotrunning,regardlessofkeystate.TheELCSsystemdoes
notincludeprovisionsforshuttingdown120-VACcircuits.
TheELCSwillbeginasequenceofeventswhenthemeasured
batteryvoltageisatorbelow12.1VDCforaperiodof30
seconds.Thesequenceofeventswillrststartwithproviding
thevisualalertLOADSHEDDINGtothevehicleoperatorfor
atleast30seconds.Anaudiblealert,whichconsistsofa
continuoustonegreaterthan3secondsandlessthan6seconds
induration,willcoincidewiththestartofthevisualalert.
Theaudiblealertcanbedisabledbyavehiclemaintainerif
desired.Thesequencewillthendisableapredenedgroup
offeatures/electricalloads.Thesewillremaindisableduntil
thevehicle'skeyswitchtransitionstotheAccessoryorON
positions,andthemeasuredvoltageisabove12.1VDC.
Engine
Theengineforthisvehicleisanelectronicallycontrolleddiesel
engine.AseparateEngineControlModule(ECM)monitorsand
149