What was found
A/I ORD DUE BRAKE TEMP MSG MLG BAY OVERHEAT DETECTION SYS, MAIN LANDING GEAR OVERHEAT FAIL ON EICAS. DECLARED EMERGENCY. FLT CXLD. AFTER ORD DEPARTURE AND GEAR DOWN FOR MEL 26-19 UNABLE TO COMPLY WITH BREAK TEMPERATURE PORTION. BRAKES DID NOT COOL AT ALL. FOUND LT MLG BAY TEMPERATURE HARNESS OPENED AT CONNECTOR TC11P2 REF MEL 26-19. REPLACED LT MLG BAY TEMPERATURE SENSOR HARNESS IAW AMM 26-14-04. OPS CHECK GOOD. MEL ITEM RESTORED. REINSTALLED LT MLG WHEEL BIN IAW AMM 53-83-89-400-801.