What was found
FLIGHT 2141. DOOR PAX FWD OPEN MASTER WARNING ON EICAS CLIMBING THROUGH 7,000 FEET PRESURIZATION NORMAL. MESSAGE CONTINUED TO FLASH AFTER CONFIRMING NORMAL DOOR INDICATION WITH FLIGHT ATTENDANT . RETURNED TO FIELD. LANDING UNEVENTFUL. REMOVED FROM SERVICE AND PLACED ON MEL. STARTED TROUBLE SHOOTING L1 DOOR PER FIM TASK 52-72-810-803-A PAR 51-75(C). NOTE: FOUND BROKEN WIRE AT HINGE POINT (MARKED) REPLACED L1 DOOR CLOSED SENSOR P/N 170-68060-405 INAW E175 52-72-20-000/400-801-A. PROX SENSOR NOT DISTURBED. PLACARDS REMOVED FROM ACFT & AML CLEAR DEFECT MTX PROCEDURES REVERSED. RETURNED TO SERVICE.