What was found
UPON DECENT, CREW EXTENDED LANDING GEAR BUT DIDN'T GET GEAR LOCK LIGHT FOR THE LEFT MAIN. CREW DISCONTINUED THEIR APPROACH AND PICKED UP A NEW IFR CLEARANCE FROM ATC AND WAS PUT INTO HOLD TO DO THEIR EMERGENCY CHECK LIST. AFTER BLOWING THE GEAR BOTTLE, THERE WAS STILL NO GREEN LIGHT FOR THE LEFT MAIN. AIRCRAFT DECLARED AN EMERGENCYAND DIVERTED TO MTJ, LANDING WAS UNEVENTFUL. AIRCRAFT WAS FERRIED TO GJT WITH GEAR DOWN AND LOCKED TO FACILITATE MAINTENANCE. MX REPLACED LT MAIN GEAR ACTUATOR IAW MM 32-30-04 AND PERFORMED SATISFACTORY GEAR SWING. AIRCRAFT RETURNED TO SERVICE.