1999 Ski-Doo Factory Shop Manual Volume Three, Page 236Get this manual

Section 06 ELECTRICAL Subsection 06 (TESTING PROCEDURE)
INSPECTION OF AC CIRCUIT ISOLATION
290 Models If AC circuit is not isolated from frame, headlamp beam will weaken

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