What was found
LEFT BLEED TRIP OFF LIGHT ON AT 30,000'' IN CLIMB. RAN QRH, LIGHT OFF THEN ON IN A MINUTE OR TWO. TROUBLE SHOT WITH GUM MTCE & LIGHT CAME ON AGAIN. PSI BOTH 45. PERFORMED FIM TASK 36-10-00-810-809, FOUND FAULTY PRECOOLER CONTROL VLV SENSOR. R & R 390 SENSOR IAW AMM 36-12-03. RAN NR 1 ENG AT 80% N1 FOR 15 MINS. BLEED PRESS 45 PSI. OPERATIONS CHECKED GOOD. ROTABLE PARTS CHANGE WAS INDICATED. TT 1677612 SN OFF 04655 SENSOR, PRECOOL OFF 29-3626-9-9001 4655 ON 29-3626-9-9001 5183.