so what check your fuse for slight melting? if it looks like it is then you need to change the fuse holder,fuses and fans?

just the fuse holder. its the corrosion of the fuse in the fuse holder which makes a high resistance joint and heat ensues as current passing makes things very hot/melty

if the fuse looks corroded in there, clean it up, some white grease, reinsert it and order a new fuse holder.
 
Im very paranoid now always checking the fuse holder, any slight smell of burning and im under the bonnet normally something ive driven past though! and ive invested in a fire extinguisher.