What was found
AIRCRAFT WAS GROUNDED: DURING INITIAL TAKEOFF ROLL PRIOR TO 80 KNOTS THE RIGHT AFT CABIN DOOR OPEN ILLUMINATED. WE DISCONTINUED THE TAKEOFF. THE LIGHT DISAPPEARED THEN CAME BACK ON DURING TAXI IN. REMOVED DOOR LINING, CHECKED RIGGING OF PROXIMITY SWITCH 17WV AND 15WV. FOUND INSULATION BLANKET AND LINING INHIBITING FULL CLOSURE OF DOOR HANDLE, VERIFIED RIGGING OF SWITCHED, REINSTALLED INSULATION AND LINING. VERIFIED DOOR HANDLE FULL LATCH PER AMM 52-21-00.