What was found
DURING CLIMBOUT PASSING THROUGH 16000 FT A ODOR WAS DETECTED IN COCKPIT. AIR CONDITIONER BLOWER WAS TURNED OFF WHICH APPEARED TO HELP. ALL OK UNTIL THROTTLES PULLED TO IDLE AND RADIO DESCENT INITIATED. DECIDED TO RTB AND FOLLOWED SMOKE/FUMES IN COCKPIT CHECKLIST WITH NO DIFFERENCE IN ODOR. DURING DESCENT TO 10000 FT CABIN BLOWER C/B WAS FOUND POPPED, COCKPIT AIR WAS TURNED ON WHICH LESSENED THE ODOR. O2 MASKS WERE PULLED OUT AS A PRECAUTION BUT WERE NOT NEEDED.