What was found
DURING TAXI INBOUND, STARTED THE APU. A STRONG ELECTRICAL BURNING ODOR, WITH APU OFF, NO ODOR. PERFORMED VISUAL INSPECTION OF TAILCONE AREA AND ADJACENT CONTROL SURFACES NO EVIDENCE OF HEAT DAMAGE. INSPECTED APU, NO OBVIOUS DAMAGE NOTED. RAN APU AND LOOKED FOR LEAKS, NONE NOTED. PLACED APU BLEED SWITCH TO ON AND BOTH AIR CONDITIONING PACKS TO AUTO & HIGH SETTINGS, NO ODOR NOTED IN CABIN AREA. APU RUN FOR 2 1/2 HOURS WITH LOADS, ALL CHECK NORMAL. NOTE APU WAS REPLACED IAW AMM 49-11-00-710-801.