We have a 1640 combine, when it is windy the rotary air screen spins slower and causes the alarm to buzz. It only happens when we are combining torwards the south and the wind from the west slows the screen. We have replaced the sensor and it did not help. The radiator seems to be clean. We know the green wire in the cab behind the monitor is the wire that goes to the sensor but if you disconect the wire it opens the circut and the alarm goes on. Any suggestions?