IMPORTANT
Duringtheoperationofthemachine,ifthePTOshutsdownand
theconsoletemperaturewarninglightisilluminatedbecauseof
excessiveenginecoolanttemperature,avoidshuttingofftheengine.
Underthiscondition,pushthePTOknobdown,slowlydrivetoa
safeatarea,movethethrottlelevertotheSLOWposition,pressthe
tractionpedal,andsettheparkingbrake.Allowtheenginetobe
idleforseveralminuteswhileitcoolstoasafelevel,andcheckthe
coolingsystembeforereturningthemachinetoservice.
TestingthePTOSwitch
1.Parkthemachineonalevelsurface,lowerthecuttingdeck,settheparking
brake,andshutofftheengine.
2.BeforeyoudisconnectthePTOswitchfortesting,ensurethatyoutestthe
switchanditscircuitwiringasaSCMinput;refertoStandardControlModule
(SCM)(page6–3).
3.IftheSCMveriesthatthePTOswitchandcircuitwiringarefunctioning
correctly,nofurtherswitchtestingisnecessary.
4.IftheSCMdeterminesthatthePTOswitchandcircuitwiringarenot
functioningcorrectly,thentestthePTOswitchasfollows:
A.Removethe4thumbscrews(item3inFigure133)thatsecurethecontrol
paneltothefueltank.
B.EnsurethatthekeyswitchisintheOFFposition.Disconnectthewire
harnessconnectorfromthePTOswitch.
C.ThePTOswitchterminalsareidentiedinFigure134andthecircuitryof
thePTOswitchisshownintheCircuitLogicT able(page6–33).Withthe
useofamultimeter(ohmssetting),testtheswitchfunctionstodetermine
ifthecontinuityexistsbetweenthevariousterminalsforeachswitch
position.Checkthecontinuitybetweentheswitchterminals.
CircuitLogicTable
SwitchPositionClosedCircuitsOpenCircuits
OFF(DOWN)COMB+NCB
COMC+NCC
COMB+NOB
COMC+NOC
ON(UP)COMB+NOB
COMC+NOC
COMB+NCB
COMC+NCC
D.ReplacethePTOswitchiftestingdeterminesthattheswitchisdamaged.
E.IfthePTOswitchtestingiscorrectandacircuitproblemstillexists,check
thewireharness;refertotheElectricalSchematicsandWireHarness
Drawings/DiagramsinAppendixA(pageA–1).
F.Afteryoucompletethetesting,connectthemachinewireharness
connectortothePTOswitch.
G.Securethecontrolpaneltothemachinewiththe4thumbscrews.
Groundsmaster
®
3280-D/3320
Page6–33
ElectricalSystem:TestingtheElectricalComponents
05138SLRevB