What was found
WHILE CLIMBING THROUGH 6-7000 FT AFTER TAKEOFF, AMBER AFT AIRSTAIR LIGHT ON S/O PANEL CAME ON. RAN QRH & RETURNED TO DEPARTURE. LIGHT REMAINED ON UNTIL JUST AFTER LANDING WHEN ACFT DEPRESSURIZED. RELEASED FOR SERVICE FOUND MARGINAL ADJUSTMENT ON S395 (AFT AIRSTAIR HANDLE POS SW) & ADJUSTED IAW AMM 52-70-001-5. FOUND RT AFT STAIR UPLOCK SW CORRODED. R & R SAME. FOUND ACTUATOR ASSY ON LT AFT AIRSTAIR UPLOCK SW BAD, NOT RIDING CORRECTLY ON QUADRANT CRANK ARM & RIGGED. R & R S268 ACTUATOR ASSY & ADJUSTED IAW AMM 52-70-001-5. AIRSTAIR WARNING LIGHTS OP CHECK GOOD. ACFT OK FOR CONTINUED SERVICE. CHECKED AFT AIRSTAIR RIG, FAIR, & OPS CHECK REF MM 52-62-001-5. CHECKS GOOD.