What was found
SHORT FINAL, LEFT AFT CARGO DOOR LIGHT ON F/E PANEL ILLUM FOLLOWED BY IMMEDIATE PRESSURE DROP IN CABIN. ACFT WAS ALREADY CONFIGURED FOR LANDING, LANDED SUCCESSFULLY, NO FURTHER PROBLEMS. DOOR 4L SWITCH NOT WORKING DUE TO TRACK CAM AND SLIDER BROKEN. REPLACED TRACK CAM AND SLIDER, OPS OK. C/B'S DO NOT POP.