As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER THREE HOURS OF CRUISE, AT FL340, CLIMBED TO FL360. ON REACHING FL360, NOTICIED WING ANTI-ICE LT VALVE OPEN LIGHT WAS ILLUMINATED BRIGHT BLUE. LIGHT REMAINED BRIGHT BLUE APPROX 5 MINUTES, THEN EXTINGUISHED FOR REMAINDER OF FLIGHT. ACFT GROUNDED. PERFORMED THE WING ANTI-ICE FAULT ISOLATION TEST. COULD NOT DUPLICATE DEFECT IAW FIM 30-11 TASK 803. THERE IS NO MAINTENANCE HISTORY WITHIN THE PAST 30 DAYS.