Right new rads in, and everythings wired up, and the fans still aint kicking in when they should be

I've bridged the fan switch with a wire in the end and they still aint kicking in, but when i put the wire in i can hear a 'clicking' sound from near the fusebox, the only fuse i can see is a 30a one which is fine, any other ideas?!?!?! if i put a wire from the batt straight too the fans they come on so the fans are ok