As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ANTI-ICE LIGHT ON MASTER CAUTION KEEPS COMING ON. TAT WAS SHOWING 99C THEN BACK TO 12C GROUNDED. ACFT EQUIPED WITH AUTO FUNCTION ON ANTI-ICE PANEL, HEATER FOR TAT PROBE WAS ON AT GATE. AFTER PROBE COOLED. RAN TAT PROBE CHECK REF 34-21, TASK 813 & ADIRU BITE REF. 34-21 TASK 801. GROUND VERIFICATION TEST GOOD. NO PREVIOUS HISTORY.