As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT WING DE-ICE VALVE ILLUMINATED AND REMAINS ON WHEN WING ANTI - ICE SWITCH TURNED ON. ASSOCIATED ANTI-ICE LIGHT AND MASTER CAUTION LIGHTS ILLUMINATE. ALL LIGHTS EXTINGUISH WHEN WING ANTI-ICE SWICH IS TURNED OFF. GROUNDED - YES. REMOVED AND REPLACED LH WING THERMAL ANTI-ICE VALVE REF B737-9 AMM 30-11-11. OPS CHECK GOOD.