I am making this so people have the information they need for this. Most sources including wjjeeps have very little information on this. I am hoping that this post is moved to the how-to section as I think it needs to be there.


The 2001 WJ - and only the 2001's have a harness underneath the dash while the other years only have just the brake controller cable. The famous blue one.
See the picture below. But when I found mine it was behind a good few cables to the far left side of the foot weal. You kinda have to fish it out.
(See Picture)



Now unlike what wjjeeps says; the pigtail is NOT discontinued. it just has a new part number. 56020143AD

As of this posting I see a few postings on ebay for it at around 30-40$.
It can be ordered from morpar but my dealerships price is 97.00$

But to be honest. You do not need the harness. You can just splice into the cables. Unlike all the other years you do not have to run power cables and give it its own fuse.

Wiring-
Thicker White/brown cable near the edge - Power 12v
Blue - Trailer Brake
Thiner White/brown - Vehicle brake
Black- ground


I spent quite a while trying to find this information myself. I do hope google finds this page to make it easier on the next guy.