What was found
SEVERAL MINUTES AFTER INITIAL EXT POWER APPLICATION, EQUIPMENT COOLING WARNING HORN SOUNDS AND EICAS STATUS MESSAGE FOR LT EQUIPMENT COOLING FAN DISPLAYED. TRIED RESET, NO HELP. MAINTENANCE MESSAGE 21-14021. REPLACED EQUIPMENT COOLING FAN (LT), AND FILTER. NO HELP. FAN OPS CHECKS NORMALLY. ENVIRONMENTAL TEST ON MAT FAILS. REPLACED FLOW SENSOR, NO HELP. GROUND TEST SHOWED MESSAGE 21-14132. REPLACED FLT DECK FLOW SENSOR. ACCOMPLISHED GROUND SYS TEST, TESTS OK.