FLC OF AN LGT DECLARED AN EMER AFTER RPTED CABIN SMOKE SMELL AND AN AFT CARGO OVERHEAT WARNING. THE ACFT DIVERTED TO LAND AT THE NEAREST APPROPRIATE ARPT.

Narrative

AT 37000 FT; 100 MI E OF RNO WE HAD A R AIR CONDITIONING DUCT OVERHEAT. WE WENT THROUGH THAT PROC. ABOUT 3 MINS LATER WE HAD AN AFT CARGO SMOKE WARNING. WE WENT THROUGH THAT PROC. THE SMOKE LIGHT STAYED ON; AFT CARGO TEMP 60 DEG F. WE HAD THE FLT ATTENDANTS CHK FOR SMOKE IN THE CABIN; AND GOT DISPATCH AND MAINT CTL ON THE LINE. THE FLT ATTENDANT SAID THERE WAS A FAINT SMELL OF SMOKE IN THE AFT CABIN. I DECIDED TO DECLARE AN EMER AND DIVERT TO RNO (DISPATCHER AGREED). WE TOLD THE FLT ATTENDANT IT WAS A RED EMER. ON DSCNT THE FLT ATTENDANT SAID THERE WAS NO LONGER A SMELL OF SMOKE IN THE CABIN; AFT CARGO TEMP STILL 60 DEG F. SMOKE WARNING WENT OUT. AFTER THE FLT ATTENDANT BRIEFED FOR AN EMER EVAC; I MADE A PA EXPLAINING THAT WE WERE NOT GOING TO EVAC AS SOON AS WE LANDED. INSTEAD WE WOULD HAVE THE FIREMEN VISUALLY CHK OUT THE ACFT ON THE GND; AND IF THERE WAS NO SMOKE INSIDE OR OUTSIDE THE ACFT WE WOULD THEN TAXI TO THE GATE AND DEPLANE. THE FIREMEN VISUALLY CHKED THE AFT CARGO AREA OUT ON THE GND AND THERE WAS NO SMOKE INSIDE OR OUTSIDE THE ACFT. THE COPLT TOLD THE PEOPLE TO REMAIN SEATED AND WE TAXIED TO THE GATE. AFTER DEPLANING ALL THE PEOPLE; WE OPENED THE AFT CARGO WITH THE FIRE FIGHTERS AND THEIR HOSES STANDING BY. THERE WAS NO EVIDENCE OF SMOKE OR FIRE IN THE AFT CARGO. MY GUESS IS THAT THE DUCT OVERHEAT CAUSED THE SMOKE SMELL IN THE CABIN AND THE AFT CARGO SMOKE WARNING TO GO OFF.