As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
#2 ENGINE ANTI-ICE BLUE (COWL VALVE OPEN) LIGHT DOES NOT STAY DIM WHEN ENGINE ANTI ICE SELECTED ON (LT INTERMITTENTLY SWITCHES BACK AND FORTH) (DIM TO BRIGHT). GROUNDED - YES. REF B737-800 WDM'S 30-21-11/30-21-21 PG1, W/DP1303 OFF VALVE, SW ON, AND SHOWS BRIGHT TILL PINS 8+9 ON SAME CONN JUMPERED AND GOES DIM. SUSPECT BAD VALVE (V4). REMOVED AND INSTALLED #2 ENGINE COWL TAI VALVE REF B737-800 AMM 30-21-11. OPS CHK GOOD.