As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DESCENT WITH A TAT OF -3 WING WING ANTI-ICE WAS TURNED ON AND THE L VALVE CAUTION LIGHT REMAINED ILLUMINATED. CHECKLIST DIRECTED TO TURN OFF WING ANTI-ICE AND CAUTION LIGHT EXTINGUISHED. GROUNDED - YES. PREFORMED OPS CHECK REF B737-9 AMM 30-11-11-710-801 NO DEFECTS NOTED.