What was found
DESCENDING THROUGH 15,000 FEET ON ARRIVAL INTO MEMPHIS LEVEL THREE APU FIRE MESSAGE. FOLLOWED QRH, PULLED APU AGENT DISCHARGE HANDLE, DISPENSING BOTH FIRE BOTTLES IN ACCORDANCE WITH CHECKLIST. APU FIRE MESSAGE STAYED ON. DECLARED AN EMERGENCY WITH ATC AND SPOKE WITH CFR ON RWY 27 AFTER LANDING. NEVER HAD ANY INDICATION OF SMOKE OR FUMES AND CFR HAD NO INDICATION THAT THERE WAS A FIRE IN THE TAILCONE AREA. EMERGENCY DECLARED, FOUND APU FIRE WARNING LIGHTS L2-130 ON APU GROUND CONTROL PANEL SHORTED TO GROUND AND REPLACED L2-130 IAW 26-21-10-4 AND SWPM AND WDM 26-12-01 PAGE 4 SHEET 1. OPS CHECKED GOOD.