What was found
DURING CRUISE, WAS NOTIFIED ENGINE VALVE CLOSED, LIGHT ILLUMINATED BRIGHT BLUE ON NR 2 ENGINE WITH ENGINE RUNNING NORMAL AND ALL INDICATION NORMAL, THE LIGHT EXTINGUISHED AFTER 5 MINUTES. ACFT GROUNDED. COULD NOT DUPLICATE. AS A PRECAUTION, REPLACED NR 2 NACELLE WIRING HARNESS, IAW MM 71-51-03 & WDM 76-21-21. OPS CHECKED NORMAL, PLUS PERFORMED ENGINE RUN WITH NO DEFECTS NOTED, WITH ENG VALVE CLOSED LIGHT.