I tinkered around today & I managed to get the illuminated sills working. I connected the GROUND & the POWER wires for all 4 sills using, for each, a 5-block Wago connector (Wago 221-415; https://amzn.to/3sfKT6U). I then connected the GROUND Wago connector to a screw on the body, & used the POWER Wago connector in conjunction with a piggy-back fuse (5A) & connected it to fuse no. 32 underneath the glove-box. They all work!

My plan is to connect the GROUND & the POWER from the rear to the front sills using 2 separate Wago connectors, or maybe I should use Scotch Lock T Tap connections (https://bit.ly/3uUVPZp)...???

My burning question is: How do I get both GROUND & POWER cables from the driver side to the passenger side? Easiest way would be from driver's side footwell to passenger side footwell. Would this be possible?