VEHICLE CAUGHT ON FIRE DUE TO AN INCORRECTLY INSTALLED HEAD LIGHT DUE TO A CRACKED PLUG ASSEMBLY. VEHICLE WAS IN A FAST-FOOD DRIVE THROUGH WHEN THE SMOKE AND SUBSEQUENT FLAMES WERE SEEN. DUE TO AGE OF THE VEHICLE THE TASK OF CHANGING THE LIGHT BULB WAS FARMED OUT TO LOCAL OIL CHANGE SHOP. WHILE CHANGING THE PLACING THE NEW BULB INTO THE PLUG ASSEMBLY THE THIN PLASTIC BROKE KEEPING THE BULB FROM SEATING PROPERLY. TESTED OKAY ON REASSEMBLY BUT ONCE NIGHT CAME THE LIGHT WAS ON FOR ONLY 15 MINUTES AND IGNITED THE INNER HEAD LAMP ASSEMBLY AND SUBSEQUENTLY MORE OF THE ENGINE COMPARTMENT. FORTUNATELY, THE FAST-FOOD RESTAURANT CAME OUT WITH AN EXTINGUISHER AND PUT OUT THE FIRE. THANKFULLY, NO ONE WAS HURT HOWEVER, HAD THE FIRE OCCURRED ON THE HIGHWAY, IN A PARKING LOT UNATTENDED, OR IN THE HOMES GARAGE, THE OUTCOME WOULD HAVE BEEN FAR WORSE.