WE STARTED HAVING ISSUES WITH THE REAR DEFROSTER NOT WORKING ON THE POWER SLIDING REAR WINDOW. AFTER A SHORT PERIOD OF TIME AFTER PUSHING BUTTON TO POWER THE REAR DEFROST SMOKE WAS NOTICEABLE COMING FROM THE LOWER PART OF THE REAR WINDOW ON THE PASSENGER SIDE OF THE CAB. I THEN PUSHED THE REAR DEFROST BUTTON TO TURN OFF THE POWER LOOKED BACK INTO THE REAR VIEW MIRROR TO SEE IF THE SMOKE WOULD STOP AND SAW THE WINDOW FRACTURE AS I WAS LOOKING AT IT. *TR