my electric fan on the radiator wont shut down, we had a hot spell and it came on a fair bit when stopping/parking...now yesterday i find it wont stop even when the engine is cold ie after being parked all night..anybody had this problem? know how to fix it ? (probably replace fan temperature signal sender switch or something which needs the covers taken off which I want to avoid as they all clip on with plastic bits which have a nasty habit of breaking off in my experience of taking plastic covers off stuff)