What was found
SEA FLIGHT NR 2257: PROP DEICE CAUTION LIGHT ILLUMINATED. RECYCLED PROP HEAT PER CHECKLIST AND LIGHT CAME BACK ON. AIRCRAFT RETURNED TO FIELD. MAINTENANCE INTERROGATED CDS AND FOUND OPEN PHASE B OPEN PHASE C AND OPEN HEATER FAULTS ON TMCU 2. C/W Q400 FIM TASKS 30-61-00-810-835, 60-61-00-810-836 AND 30-61-00-810-857 BY PERFORMING AN ELECTRICAL CONTINUITY CHECK OF THE PROPELLER DEICING HEATER ELEMENTS IAW Q400 AMM TASK 30-61-00-760-801. FOUND BROKEN HEATER HARNESS ON NR 2 PROP, NR 2 BLADE. REMOVED AND REPLACED NR 2 PROP, NR 2 BLADE HEATER HARNESS IAW Q400 AMM TASKS 61-10-06-000-801 AND 61-10-06-400-801. OPS CHECK GOOD. FAULTS DID NOT RETURN. AIRCRAFT RETURNED TO SERVICE.