What was found
AFTER TAKEOFF, PROP DE-ICE CAUTION LIGHT ILLUMINATED. CAUTION LIGHT EXTINGUSHED AFTER RUNNING CHECKLIST. NONE OF THE GREEN PROP DE-ICE LIGHTS CAME BACK ON IN "ON" OR "TEST" MODE. RETURNED TO FIELD AND ACCOMPLISHED A UNEVENTFUL LANDING. INTERROGATED CDS, FOUND NO FAULTS. PERFORMED FUNCTIONAL TEST OF PROP DE-ICE SYS IAW AMM TASK 30-61-00-720-801. PROP LIGHTS ON ICE PROTECTION PANEL WOULD NOT ILLUMINATE, NO FAULTS WERE LOGGED IN CDS. R & R ICE AND RAIN PROTECTION PANEL IAW AMM TASK 30-10-01-000-801/30-10-01-400-801. OPS CHECKED GOOD. RETURNED TO SERVICE.