2003 Ski-Doo ZX Series Factory Shop Manual, Page 296Get this manual
Section 06 ELECTRICAL Subsection 06 (TESTING PROCEDURE)
INSPECTION OF AC CIRCUIT INSULATION
Fan Cooled Electric Start Models If AC circuit is not insulated from frame, headlamp beam will weaken
INSPECTION
Disconnect regulatorrectifierConnect one digital ohmmeter probe (needle ohmmeter will not offer enough precision) to frame and other probe to YELLOW wire (2-MO)Measured resistance must be infiniteIf such is not the case, it means there is connection between AC circuit and frameDisconnect one accessory at the time to identify the faulty circuit
INSPECTION OF HEATING ELEMENTS
All Models All measurements must be performed at 21C (70F)