swiss scooby

Hi All, today my 52mm Defi Oil Temp gauge (DF02201) started to 'bounce' around. Eventough the temperature was rising to regular temp (~90 degree) from cold, every now and then the needle bounced down and up again. I am now wondering if it is the gauge, the sensor or the control unit that causes this problem. I have this gauge (with Oil Press and Turbo) for over 8 years now and haven't had any issues so far. Your help is very much appreciated. BTW, I am happy that it isn't the Oil Press meter. Rgds, Daniel