Service Manual

UpLimitSwitches
g032277
Figure285
1.Uplimitswitch(left)2.Sensingplate
Thecuttingdeckuplimitswitchesarenormallyopenproximityswitchesthatare
attachedtothebracketslocatedonthetractionunitframe(Figure285).The
sensingplatesusedfortheswitchesarelocatedonthecuttingdeckliftarms.
Whenacuttingdeckisintheloweredposition,thesensingplateisneartheup
limitswitchandtheswitchisclosed.Thisclosedswitchisusedasaninputfor
thecontrollertoprovidecurrentowtothecuttingdeckhydraulic-solenoidvalve
whenPTOisengaged,allowingthecuttingdecktooperate.
Whenacuttingdeckisraised,thesensingplateismovedawayfromtheup
limitswitchandtheswitchopens.Thisopenswitchisusedasaninputforthe
controllertopreventthecurrentowtothecuttingdeckhydraulic-solenoidvalve,
preventingthecuttingdeckfromoperating.
TestingtheUpLimitSwitch
Note:Monitortheoperationofauplimitswitchanditscircuitwiringwiththe
InfoCenterbeforedisconnectingtheswitchfortesting;refertoInfoCenterDisplay
(page5–13).IftheInfoCenterdisplayveriesthattheuplimitswitchandcircuit
wiringarefunctioningcorrectly,testingoftheswitchisnotnecessary.
1.VerifywiththeInfoCenterdisplaythatthedeckpositionswitchandcircuit
wiringarenotfunctioningcorrectly.
2.Parkthemachineonalevelsurface,lowerthecuttingdecks,shutoffthe
engine,settheparkingbrake,andremovethekeyfromthekeyswitch.
3.Disconnecttheuplimitswitchthatrequirestestingfromthemachinewire
harness.
4.Connectamultimeter(ohmssetting)acrosstheswitchconnectorterminals
tocheckthecontinuityoftheswitch.
5.Withthecuttingunitintheloweredposition,ensurethatthereisacontinuity
(zeroresistance)acrosstheswitchterminals.
6.Raisethecuttingunit.Ensurethatthereisnocontinuity(inniteresistance)
acrosstheswitchterminals.
7.Replacetheswitchasrequired.Connecttheswitchtothemachinewire
harness.
ElectricalSystem:TestingtheComponent
Page5–96
Groundsmaster5900TractionUnit
08159SLRevC