What was found
LEFT OIL QUANTITY SHOW EITHER --(DASHES) OR EN ROUTE. ALL OTHER INDICATIONS NORMAL. DURING DESCENT OIL PRESSURE DROPPED TO 32 PSI, IDLE - 25 PSI AT 1.4 EPR. RAN QRH AND SECURED LEFT ENGINE. MAINTENANCE DEPARTMENT PERSONNEL INSPECTION FOUND DIFFERENTIAL PRESSURE SWITCH LOW OIL PRESSURE SENSE LINE BROKEN AT PORT LP5. REMOVED AND REPLACED OIL PRESSURE DIFFERENTIAL SWITCH SENSE LINE IAW AMM 79-36-01, LEAK CHECK GOOD, NO DEFECTS NOTED, AIRCRAFT RETURNED TO SERVICE.