[MENTION=153213]2016 4Runner SR5[/MENTION]
That is correct. I just slid the wires out of the harnesses that came with the relays and slipped them into the new box.
The relays have a tab on them for hard mounting, I just broke it off. When I have all of the pigtails wired up to the fuses and such, I am going to fill in the bottom with silicone to insure a good waterproof box. I am also going th o-ring the top and bottom of the box. This will require me making a 1.5mm grove all the way around it for the o-ring to sit in. It is a pita, but for less than $30 all said and done, you really can't beat it. Honestly, that may be a bit overboard, but I just like my electronics to stay nice and dry. I'll make a jig with 2x4 pieces of wood and sandwich the box inside of it. Then with the dremel fixed on a mount I will set it and slid the box through making a perfect grove all the way around.
The box.
https://www.amazon.com/gp/product/B07K1958JT/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
The relay pack..
https://www.amazon.com/gp/product/B017VDI0GY/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1