What was found
EMERGENCY LANDING - FLT 0280 - ON APPROACH, EN ROUTE WITH LANDING GEAR SELECTED DOWN GEAR DID NOT EXTEND, MANUALLY SELECTED GEAR DOWN AND DECLARED EMERGENCY. MAINTENANCE PERFORMED WIRING CHECK AND FOUND RESISTANCE ON LT MAIN LANDING GEAR (MLG) DOOR OPEN PROXIMITY SENSOR HIGH, REMOVED AND REPLACED LT MLG DOOR PROXIMITY SENSOR IAW AMM 32-31-73, OPERATIONAL CHECK WAS GOOD.