JDUB
Full Access Member
Putting a larger fuse where it does not belong results in the possibility of drawing to much current through the small gauge wire. Now the fuse will be the wire and as it gets hot it could cause a fire. Its not critical to me in your truck, but you may feel different. Stick to the fuses it says to use and you don't have to worry about it then... But like I said its your truck do what makes sense to you...
I haven't dug into the up-fitter switch wiring yet, but soon! So Ford used different gauge wire for each switch to match the fuse amperage? Sounds like a lot of extra work from the manufacture...