2003 Polaris ATV Trail Boss 330 Factory Service Manual, Page 202Get this manual

ELECTRICAL
HEADLAMP SWITCH
Follow procedure, Headlight Lamp Replacement, on Page 10.1710.18 to access connectorProbe the headlamp plug wires (Brown, Green, Yellow) at back of connectorTurn headlight onTest for battery voltage across the connections

Check continuity across pins of the left handle bar switch assemblySee illustration below
Continuity

• ATV
• Jet Ski
• Outboard Motors
• Personal Watercraft
• Snowmobiles
• Stern Drives