As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
#2 ENG ANTI-ICE COWL; VALVE OPEN LIGHT INTERMITTENTLY CHANGED FROM DIM BLUE TO BRIGHT BLUE INDICATION WITH ENG ANTI-ICE SWITCH IN THE ON POSITION. ANTI-ICE VALVE WAS IN FULLY OPEN POSITION AS ANTI-ICE INDICATION ON ENG INTRUMENTS PANEL SHOWED GREEN A/I AND N1 INDICATION MATCHED #1 ENG W/ COWL LIGHT BRIGHT BLUE. GROUNDED - YES. REMOVED AND REPLACED #2 ENG TAI VALVE. CONDUCTED ENGINE COWL TAI VALVE INSTALLATION TEST WITH ALL INDICATIONS NORMAL SIGNIFICANT SYSTEM GROUND VERIFICATION OPS GOOD REF B737-800 AMM 30-21-11-400-801.