2003 Polaris ATV Trail Boss 330 Factory Service Manual, Page 203Get this manual
ELECTRICAL
STARTER SYSTEM TESTING
Condition: Starter fails to turn motorNOTE: Make sure engine crankshaft is free to turn before proceeding with dynamic testing of starter systemA digital multitester must be used for this testWith the tester on the VDC position, place the tester's black lead on the battery negative and the red lead on the battery positive
Reading should be 12.4 volts or greater
Remove battery and properly serviceInstall fully charged shop battery to continue test
Disconnect WhiteRed engagement coil wire from the starter solenoidConnect tester black wire to battery groundConnect red tester lead to White Red harness wire at solenoidTurn on ignition switch and depress the starter buttonTester should read battery voltage
Check voltage on both sides of circuit breaker, ignition switchengine stop switch and starter buttonThe voltage on both sides should be the sameNOTE: The ignition switch and engine stop switch must be on and the starter button depressedReplace the defective component
Voltage Drop Testing