What was found
APU FAULT LIGHT ON AFTER ATTEMPTED RESTART. GROUNDED - YES. VERIFIED APU INOP, FAULT CODE 49-15217 (INLET DOOR SWITCH POWER SHOWS HIGH CURRENT), REF B737-900 FIM 49-10 TASK 809. APU BITE SHOWS NO CURRENT FAULTS. FOUND BACKSHELL LOOSE AND WIRE W4726-1003-20 CHAFING ON BACKSHELL AT CONNECTOR D1246. RETERMINATED ALL THREE WIRES AT CONNECTOR D1246 AND RESECURED BACKSHELL REF B737-900 WDM 49-62-11 P.4 SH.3 AND B737 SWPM 20-61-11. WIRING CHECKS GOOD, PER FIM 49-10 TASK 809. APU SHOWS NO FAULTS IN CURRENT STATUS. RAN AND STOPPED APU, REF B737-900 AMM 49-11-00-860-802. OPS CK GOOD WITH NO FAULTS. GROUND VERIFICATION SUCCESSFUL.