Temperature coolant sensor
 

Hello, I have a 2004 ,93 cabriolet, 1.8 auto with the strangest fault. I am now on the third temperature coolant sensor. The garage has reset the engine management light and fitted a new sensor each time, this time the light has come on after a week. Previously it worked fine for 11 months, since then the sensor has been replaced 3 times the machine showing a faulty sensor. Has anybody experienced this? Any advice or help will be gratefully received.
Many thanks in advance, Graham