hi,my fans have stopped working all of a sudden.the fuse is ok,the fusebox looks ok and i have put a new fan switch into my alloy rad,is there a relay that could be at fault?

 

Most likely to be the relay holder thats burnt out.

The wiring and and fuse holder/relay holder is not really up to the job of coping with the current that the fans draw when they are on.

Best thing to do imo is to make yourself a new fan wiring loom with some thicker wire and with each fan having its own relay and fuse as opposed to both of the fans having one relay and one fuse between them.

Should be working perfect after that!!

 

As said seperate loom is best, up to you if you go for seperate circuits though, as switch is usually weakest part then so seperate circuit still won't help as it still gets no switch on.
I've done away with my switch altogether and set mine to come on at 88c and go off at 82C, though if we ever get a summer might set it a bit cooler.
tabetha