I created an account just so I can answer this question. The plug for the Rear Driver side ABS sensor is directly behind the top bolt of the rear driver side Shock. When removing the bolt, it is very easy to disconnect the ABS sensor without realizing it. If you follow the cable from your rear driver side caliper or simply feel around behind the top of the shock, you'll find the plug. No need to remove tire or anything. Just crawl under to verify if it's connected.
Good luck to anyone finding this.