WHILE DRIVING AT 35 MPH CONSUMER WAS NOTIFIED BY A PASSING MOTORIST THAT TRUNK WAS ON FIRE. UPON INSPECTION, IT HAD BEEN DETERMINED THAT FIRE STARTED IN THE REAR TAIL LIGHT. ONE OF THE OCCUPANTS SUSTAINED THIRD DEGREE BURNS. FORD ADVISED THAT THE CAUSE OF THE PROBLEM IS UNKNOWN. *AK *TS *NLM