FuelPumpRelay(Groundsmaster3320)
g223021
Figure173
1.Coilterminal
3.Normallyopenterm
2.Normallyclosedterm
4.Commonterminal
TheGroundsmaster3320usesarelaytoenergizethefuelpump.Thefuel
pumprelayisattachedtothesupportbracketinsidetherightsideframenear
thefuellter.
TestingtheFuelPumpRelay
Note:Priortotakingsmallresistancereadingswithadigitalmultimeter,short
themetertestleadstogether.Themeterwilldisplayasmallresistancevalue
(usually0.5ohmsorless).Thisresistanceisduetotheinternalresistanceof
themeterandtestleads.Subtractthisvaluefromthemeasuredvalueofthe
componentyouaretesting.
1.Locaterelayanddisconnectthemachinewireharnessconnectorfromthe
relay.
2.Usingamultimeter(ohmssetting),measurecoilresistancebetweenterminals
85and86(Figure173).Resistanceshouldbebetween70and90ohms.
3.Connectmultimeter(ohmssetting)leadstorelayterminals30and87.
Groundterminal86andapply+12VDCtoterminal85.Therelayshould
makeandbreakcontinuitybetweenterminals30and87as+12VDCis
appliedandremovedfromterminal85.
4.Disconnectvoltagefromterminal85andmultimeterleadfromterminal87.
5.Connectmultimeter(ohmssetting)leadstorelayterminals30and87A.Apply
+12VDCtoterminal85.Therelayshouldmakeandbreakcontinuitybetween
terminals30and87Aas+12VDCisappliedandremovedfromterminal85.
6.Disconnectvoltageandmultimeterleadsfromtherelayterminals.Connect
relaytomachinewireharness.
Groundsmaster
®
3280-D/3320
Page6–75
ElectricalSystem:TestingtheElectricalComponents
05138SLRevB