What was found
SMOKE AVIONICS BAY RED CAS: FL 410 CAS MESSAGE REPEATEDLY OBSERVED WITH NO ODOR OR VISIBLE SIGN OF SMOKE IN COCKPIT OR CABIN. LOUD WHINE AND VIBRATION LOCATED BEHIND SEAT 3 REPORTED BY FA AND CONFIRMED BY FO. QRC/QRH FOLLOWED TO QRH ITEM 11 (CABIN POWER). CAS MESSAGE, NOISE AND VIBRATION DISAPPEARED WITH THE DE-SELECTION OF CABIN POWER/CABIN OUTLETS. CAN NOT DUPLICATED NOISE OR VIBRATION ON GROUND. PHOTOS OF FAULT CODE ATTACHED. "CORRECTIVE ACTION" REPLACED AVIONICS EXHAUST FAN IAW AMM 21-54-37.