Fuse holder?

Just a generic blade type fuse holder. Judging by the green goo oozing out, looks like the 30A fuse is not enough and that sucker was heating up.

For fans, you really want to go with something more like these. These will handle the startup spike of most fans, but what size fuse to run depends on that wire rating. Looks like a #12 wire but I can't be sure. I like to run #10 min for fan power wires.

Amazon product ASIN B0753J14FG

I have that same fan controller in my spare parts bin. I wasn't happy with it. I find a lot of the lower end controllers simply aren't spec'ed out properly for reliability. It seems they undersize the wire to the bare min to get the product out the door, such as in this case. I even find fault with LMR as they supply a 200A alternator with a 4g wire and a 200A fuse. 4G wire is rated for more like 100A, and that's if it's good quality wire which i doubt it is.