Answer resubmitted as there are words omitted in my earlier response (sorry).
Check the fuse first, may be one in the relay, there was in my Renault Espace - which had blown. After I replaced the fuse it blew again until I had freed off the fan spindle. Took much time and effort and plenty of penetrating oil. Problem is the fan doesn't need to work much in winter and after several months of not turning it can seize. The other thing that can fail is the thermostatic switch which screws into the radiator. The switch is inexpensive and not difficult to replace.
ChicksFan, May 2009
