Fog Light Relay Missing and Fuse for dash illumination keeps burning out

I've a problem guys, my fuse (no 3) for the dash illumination keeps buring out? Before I start taking things apart, does anyone know what this maybe? A previous owner had fitted 2 toggle switches to the back of the console, 1 for the electric antenna and I don't know what the second does. He'd also fitted a battery cut off in the engine bay. All I've done in past few days is try the original cigarette lighter I found in the glovebox and connect the olf Ford radio cassette.

Just below where the fuse sits is a small bit where the plastics melted (where no 3 is in fusebox)

Does anyone have a foglamp relay they wanna sell or could tell me the numbers that are on it or if they know if I can replace it with one of another car.

Funny thing is the fogs were working before the dash light/fuse problem started.

Other than a little oil leek from sump, its fine and runs great!

Thanks