What was found
WHILE IN CRUISE, BOTH PILOTS NOTICED SMOKE COMING INTO THE COCKPIT FROM VENTS. BEGAN EMERGENCY CHECKLIST, THE SMOKE SOURCE WAS ISOLATED TO THE HEATER BLOWER MOTOR AND WAS SECURED. REMOVED FAN BLOWER, PN ME-630-10001-10, SN 1037, INSTALLED OVERHAULED FAN BLOWER, PN 500702-4491, SN336, IAW S61MM CH21-43-1, SA 4045-80, REV 47.