The electric fan of my car does not switch off after having been driven even very short distances, and sometimes when I have just switched on the ignition and then off without even starting the engine from cold. The engine doesn't overheat at all and everything appears normal otherwise.

My local garage replaced the switch with a new one as it had retained water from the radiator but this doesn't appear to have cured the problem. Any suggestions gratefully received. The cooling system has been checked for leaks but apparently there aren't any.