2003 Kawasaki KLF250 Service Manual., Page 266Get this manual
16-24 ELECTRICAL SYSTEM Charging System
Regulator Circuit Test-2nd Step: Connect the test light and 12 battery in the same manner as specified in the "Regulator Circuit Test-1st Step"Apply 12 to the BR (voltage monitoring) terminalCheck Y1, Y2, and Y3 terminalsIf the test light turns on, the regulatorrectifier is defectiveIf the test light does not turn on, continue the test