Thanks for all the help chaps its now sorted!!!

I found the replay and on close inspection saw some burn marks near the bottom of it, i prized it out and the pins were a little melted (as you guys suspected) I bent the pins and put the replay back and bingo the fans kicked in as the switch was still bridged. Took it for a run and everything works as it should.

Is there anything you can do to stop the fuse box melting?