yup, rear disks

 

I don't know how you can miss it... its really the only wire in that area i think... all i can say is that is behind that rear disk, make sure you jack the car so the diff is hanging.
Its like an inch or 2 thick, kinda like a film canister for a camera... with a metal rod sticking out the other end (thats likely got iron shavings all over it). The electrical "plug in" side is towards the center ofthe car, the sensor side is torward the wheel. Its located through a thick piece of metal and held there with a small bolt...

 

Just to clarify to my old post above.
If you have traction control you have two sensors, one each side right near the rear tires. A wire leads up to them. 1 or two screws and they just pop out. Take off both tires.

Cars without traction control have it on the rear pumpkin