2003 Ski-Doo ZX Series Factory Shop Manual, Page 92Get this manual
Section 03 TROUBLESHOOTING Subsection 05 (ELECTRICAL SYSTEM)
SYMPTOM CONDITION TESTINSPECTION
ON FAN-COOLED MODELS 20 FUSE ON BLACK WIRES IN FRONT OF VEHICLE IS BURNT OUTNORMAL USE1Check that big ground wire at battery is well connected to chassisaCorroded andor loose connection(s)Clean andor retighten
SYMPTOM CONDITION TESTINSPECTION