There is a wire that is connected into the wheel bearing and the other end is connected to the frame underneath the splash guard. The sensor is on the end of the wire connected to the frame. This is for the front wheels. Not sure where the rear is located. If your ABS light is on, then it is probably the sensor going bad if not the actual bearing. Be prepared to pay $150 + for each bearing. They're not cheap, but easy to replace...that is if you have to. I did mine last year and paid like $330 for both.
---------- Post added at 05:32 PM ---------- Previous post was at 05:27 PM ----------
This link could be helpful if you have to replace them, even though it is for a Jimmy, it is essentially the same process.
http://www.handymanlyness.com/archi...nt_bearing/GM_truck/hub_replace_99_Jimmy.html