just like he said... if you jack up the car you can look behind the wheel and see where the wires plug into the hub, i usually unplug and then replug to make sure i get it to snap into place (do this for all 4 sensors) if it still isn't going off then you could have a short or a bad hub which then it is easier to go get it scanned to find out which one is bad. On a side note its a long shot but there is also an under the hood fuse you may want to check