As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT AFTER ENTERING ICING CONDITIONS ON DESCENT, THE WING BUTTON ON THE OVERHEAD PANEL DID NOT DISPLAY OPEN INSCRIPTION AND RECEIVED AN EICAS ANTI-ICE FAIL MESSAGE. DECLARED AN EMERGENCY AND LANDED WITHOUT INCIDENT. ACFT REMOVED FROM SERVICE. PERFORMED ANTI-ICE OPS CHECK IAW AMM 30-00-00-700-802-A. OPS CHECKED GOOD. ACFT RETURNED TO SERVICE.