Installed on my 4runner TRD pro-2019. The built-in fuse holder was defective. I had one at home and replaced it. ***Try everything before each installation, even before removing the bumper cover***. No success with the interior fuse box, at least I can say it didn't work for me. But I tapped the IGN 10A fuse under the hood fuse box and it worked (minus very close to the fuse box under the 10mm nut). I find it easier and clearer when you have no reason not to. Loose wires require little tying for maintenance. In my opinion it definitely improves the look of the truck more than hurting your valet.