As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CAPTAIN`S MCDU EXEC LIGHT WILL NOT DIM WHEN LIGHTS DIM SWITCHED PLACED TO DIM AND EXECUTE FUNCTION REQUIRED. INTERMITTENTLY FLASHES BETWEEN DIM AND BRIGHT. ACFT GROUNDED. REPLACED MCDU 34-61-01-400-802. VERIFIED S/W CONFIG REF 34-61-00-750-802.