What was found
SEA FLIGHT NR 2286: ON TAXI OUT, AVIONICS CAUTION MESSAGE WITH ASSOCIATED HOT ED MESSAGE. AIRCRAFT RETURNED TO BLOCK. MAINTENANCE REMOVED ED AND FOUND AVIONICS AIR COOLING HOSES DISCONNECTED FROM UNIT. RECONNECTED HOSES AND REINSTALLED ED IAW Q400 AMM TASKS 31-61-01-000-801 AND 31-61-01-400-801. PERFORMED OPS TEST OF THE ENGINE DISPLAY IAW Q400 AMM TASK 31-61-01-710-803. TEST IS GOOD WITH NO REOCCURRENCE OF CAUTION OR ED MESSAGES. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.