1985-1995 Polaris ATV and Light Utility Hauler Service Manual, Page 399Get this manual
ELECTRICAL Lighting System Service (Non-Battery Models) If the lights on non-battery system should fail to operate properly and the problem is not in the control switch(es) proceed with the following test'
Disconnect the YellowRed and Yellow alternator wires from the machine harness or circuit boardUsing multitester, measure the resistance between the two wiresReadings should be between .45 and .6 ohms on 100 watt alternators and .25 to .35 ohms on 150 watt alternatorsMeasure the resistance between either wire and the engine crankcaseThe reading should indicate an open circuitSwitch the multitester to VAC and connect it between the YellowRed and Yellow wiresStart the engine and rev it to approximately 3000 RPMMeter readings should be above 25 volts A.CAre they?
Remove the recoil and flywheelInspect the flywheel magnets, stator coils and stator wire harness for damageRepair or replace any component found to be damaged