What was found
APU WILL NOT START. FAULT LIGHT ILLUMINATED. GROUNDED - YES. INITIAL INSPECTION FOUND APU INLET DOOR SWITCH CONNECTOR D1246 LOOSE. RESECURED CONNECTOR AND REVERSED MEL 49-6C MX PROCEDURES PER B737-800 AMM 49-00-00-440-805. 2 CBS PULLED AND RESET. ACCOMPLISHED APU INLET DOOR TEST PER AMM 49-15-00-700-801. ADJUSTED APU INLET DOOR PER AMM 49-15-00-800-801. REACCOMPLISHED APU INLET DOOR TEST. APU INLET DOOR OPENS AND CLOSES WITHIN LIMITS TAKING APPROX 17 SEC. CYCLED INLET DOOR 3 TIMES AND OPERATED APU 3 TIMES PER AMM 49-11-00 NO FURTHER DEFECTS NOTED. ALL GROUND TESTS SUCCESSFUL.