What was found
PILOT OBSERVED HIGH DISCHARGE RATE ON AMMETER APPROXIMATELY 45 MINUTES INTO FLIGHT. NO HIGH VOLTAGE LIGHT INDICATION. PILOT MADE PRECAUTIONARY LANDING. REPLACED OVERVOLTAGE LIGHT ASSEMBLY AND OVERVOLTAGE SWITCH. ALL OTHER COMPONENTS BENCH CHECKED WITH NO DISCREPANCIES. OPERATIONAL CHECK WAS SATISFACTORY AND AIRCRAFT WAS RETURNED TO SERVICE. SUBMITTER SUGGESTED INSPECTION CHECKLIST REVISION TO INCLUDE TEST OF HIGH VOLTAGE INDICATING SYSTEM.