[yelkenli]

Question for my solution below, Can I run wires between the radar unit and the car body? Toyota avoided this area. It seems like a good path though.
see attached pic.

Thanks for the recommendation. eTrailer was helpful, but they had no T-1 to flat-4 harness of about 5 feet long. They have a Universal kit, but my solution below is essentially that, and I need to get my car back on the road.

My solution is to run the Toyota harness as far as it will go under the bumper cover. Then cut the flat-4 connector off and splice in an extension.
Cover these with conduit and bring the conduit out of the cover at the hitch.
I have magnetic tie points to support along the way with zip ties.

 

[yelkenli]

I cannot really see it in this picture. For mine, I don't see how it can reach to the reciever. It is possible it is made wrong, as there is some slack inside the car before the harness crosses the grommet. I tried to pull this slack, but the grommet is installed in a cut in the conduit.