There is a bracket right behind the brake rotor that holds the connector. From there is runs along the a arm, then up into the wheel well. (Take the plastic splash cover off). The pass side runs up to, and along the top of the engine cradle.
I can't speak for the drivers side, my pass side harness was bad, and the drivers side hub was bad.
Key on, engine off unplug the connectors. You should see close to 5v between the two pins coming from the car harness.
You can also switch your meter to ohms and measure the two pins looking at the hub. You should have some resistance (I forget the value). But if you see an open circuit there, then it's the hub that is bad.
The factory piece is 2 wires, inside of plastic tube, inside wire loom. Once I pulled back the wire loom, I found the bad spot. It seems like that factory plastic tube holds moisture in, gets brittle and causes problems.