As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT WING ANTI-ICE "L-VALVE" MASTER CAUTION LIGHT ILLUMINATED WITH THE WING ANTI-ICE SWITCH IN THE ON POSITION THE "LVALVE" MASTER CAUTION LIGHT WENT OUT WHEN THE SWITCH MOVED BACK TO THE OFF POSITION. GROUNDED - YES. FOUND AND REMOVED WATER FROM ANTI ICE VALVE INLET TUBE. PERFORMED OPS CHECK REF B737-9 AMM 30-11-11. OP CHECK NORMAL, NO FAULTS NOTED.