What was found
AFTER T/O FLAPS RETRACTED NORMALLY; PASSING 6000 AMBER LIGHT FLAP TRANSIT LT ILLUMINATE AND. #4 FLAP INDICATOR ILLUMINATED AMBER ON OVERHEAD PANEL. AIRSPEED WAS 250 AND HIT 25O DURING TROUBLESHOOTING ; THEN DECREASED TO 210. LIGHTS CAME AND WENT W/FLAPS. UP. NORMAL INDICATIONS W/FLAPS EXTENDED. NO ROLL NOTED. AMBER LTS ILLUMINATED AFTER LANDING W/FLAPS UP. / [01] BITE OF FSEU SHOWS FAULT MSG 27-81222. PERFORMED FIM 27-88 TASK 805. FOUND NO FAULTS WITH AIRCRAFT SIDE WIRING. REPLACED K-FLAP #4 RETRACT SENSOR S174 IAW M/M 27-88-11.