What was found
NR 1 COWL ANTI ICE LIGHT ILLUMINATED ON POWER UP TO TAXI FOR DEPARTURE. GROUNDED - YES. R & R ENG COWL TAI VALVE PER AMM 30-21-11. VALVE OPS CK NORMAL. BUT AMBER LIGHT NOW ILLUMINATES DIMLY ALL THE TIME. PERFORMED FIM 30-21 TASK 801. FOUND CONTINUITY BETWEEN PINS 1 AND 2 ON OVER PRESSURE SWITCH. SWITCH REQUIRES REPLACEMENT. REMOVED & REPLACED NR 1 ENGINE ANTI ICE PRESSURE SENSOR. INSTALLATION TEST PASSED PER AMM 30-21-21.