As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PROBE HEAT A SWITCH IN AUTO THE L ALPHA VANE ANNUNCIATOR DOES NOT ILLUMINATE. GROUNDED - YES. L AOA VANE HEATS GOOD. ANNUCIATOR NOT ILLUM. SUSPECT CONTROL PANEL. REMOVED AND REPLACED WINDOW/PITOT HEAT MODULE REF B737-800 REF AMM 30-41-41. OPS CHECK GOOD.