What was found
CREW EXPERIENCED AN AILERON TRIM FAIL. INVESTIGATION REVEALED NO CONTINUITY IN TRIM WIRE FROM THE AILERON TRIM ACTUATOR. VISUAL INSPECTION REVEALED A NICK IN WIRE NEXT TO CONNECTOR WITH APPARENT CORROSION. STRIPPING THE WIRE BACK FROM CONNECTOR PIN FOUND CORROSION 18" ALONG THE WIRE WITH A BREAK IN THE WIRE. CORROSION HAD COMPLETELY SEVERED THE WIRE. THERE HAS BEEN NO REPAIRS TO THIS AREA SINCE THE AIRCRAFT WAS NEW. SUGGEST MAINTENANCE CREWS LOOK AT THE AILERON TRIM WIRES NEXT TO TRIM ACTUATOR ON SUBSEQUENT INSPECTIONS.