SINCE THE VEHICLE WAS 3 YEARS OLD THE HEATER FAN WHEN SET ON THE LOWEST TWO SETTINGS , WILL START TO SMOKE AND ONE CAN SMELL BURNING UNDER THE DASH. IT WILL STOP WHEN FAN SWITCH IS ON 3,4 OR 5 SETTING. CONTACTED FORD YEARS AGO THEY SAID NOT UNDER WARRENTY. ON 9/3/01 MECHANIC TEST DROVE VEHICLE WITH FAN SET ON 2, CAB FILLED WITH SMOKE HAD TO STOP IN MIDDLE OF A BRIDGE COULD NOT SEE.*AK