What was found
EMERGENCY DECLARED, LANDING UNEVENTFUL & ACFT NOT OVERWEIGHT. DURING CRUISE, LT ENG REVERSER UNLOCK LIGHT ILLUMINATED. QRH PROCEDURES FOLLOWED, LIGHT DID NOT EXTINGUISHED. ENG OPERATED AT IDLE TILL LANDING. R & R & TESTED THE UPPER THRUST REVERSER LATCH INDICATING SWITCH IAW AMM 78-32-03. SYS CHECKED NORMAL.