What was found
CLIMBING THROUGH FL220, REV CAUTION ICON ON LT N1 AND L REV UNLOCKED CAUTION CAME ON INTERMEDIATLEY THEN WENT AWAY. ABOUT 10 SEC LATER MSG RETURNED AND STAYED ON. AIRPLANE YAWED TO THE LT AND WE RAN THE QRH PROCEDURE- WHICH LED TO ENG SHUTDOWN. F/A NOTICED YAW AND VIBRATION. VIBRATION CONTINUED UNTIL SHUTDOWN. EMERGENCY DECLARED. REMOVED AND REPLACED LT T/R SWITCH AND AFDL 537960-1 LT T/R STOW SWITCH RIGGING AND OPS CKS. ACFT OK FOR SERVICE AT THIS TIME.