What was found
DURING FLT AT 800 FT MSL AND 90 KTS, RIGHT FLASHING MASTER CAUTION ILLUMINATED WITHOUT ANY OTHER WARNING LIGHTS OR AUDIO. ALL INSTRUMENTS INDICATED NORMAL. WHEN TAXING INTO PARKING MASTER CAUTION FLASHED INTERMITTENTLY. TRIED TO RESET USING BOTH CYCLICS. TEST FLIGHT: RIGHT FLASHING MASTER CAUTION ILLUMINATED FOR APPROXIMATELY 20 SECONDS WITHOUT ANY OTHER WARNING LIGHTS OR AUDIO. ALL INSTRUMENTS INDICATED NORMAL. REPLACED WARNING UNIT (IPC: 31-55-01-01-10B) IAW AMM 31-50-00, 4-1. FUNCTIONAL TEST OK.