What was found
AFTER START #1 ENGINE ANTI-ICE COWL VALVE LIGHT ILLUMINATED BRIGHT WITH AMBER TAI INDICATION. CYCLED SWITCH AT TAXI POWER 30% N1 AND 50% N1. NO CHANGE. FOLLOWED QRH. GROUNDED - YES. REFERENCE B737-800 WDM 30-21-11, FOUND #1 ENGINE COWL ANTI-ICE VALVE CONNECTOR DP1303 LOOSE. RECONNECTED. ACCOMPLISHED OPERATION CK OF #1 ENGINE TAI NOSE COWL VALVE OPS CK GOOD. NO FAULTS NOTED. REF B737-800 AMM 30-21-00-710-801.