Hey Guys you may see me posting a lot regarding my car, Its a well known fact that this car is a peice of crap Wish I kept my 86 Monte Carlo. I have been hearing a noise which I thought was my crappy new walmart winter tires but now Im thinking its a Wheel barring. Are the ABS Wheel Sensors just on the front wheels or all 4?? If its the front I might as well change them both at once, I did the one front already back in 2010 Im just not sure which wheel it is. Any suggestions would really help.

Yes, the ABS sensors are located at all 4 wheels.

If you changed a sensor, you actually changed a whole wheel bearing which has the ABS sensor built into it.

Which means your spending around $100 per wheel just to replace a wheel bearing.