What was found
AMBER CABIN DOOR SEAL LIGHT CAME ON AFTER TAKEOFF LEVELED OFF AT 9000. ON APPROACH IT WENT OUT AFTER BEING AT 3000 FT FOR A FEW MINTUES. OPENED CABIN STEPS AND AFT SURROUND OF MAIN CABIN DOOR FOR ACCESS TO INFLATION/DEFLATION VALVES. FOUND MAIN CABIN DOOR DEFLATION VALVE OUT OF ADJUSTMENT AND LOOSE, NOT CLOSING ALL THE WAY. ADJUSTED VALVE IN REF TO MM 52-10-04. LEAK CHECK AND OPS CHECK NORMAL 12/20/08 CLOSED STEPS AND AFT DOOR SURROUND.