ABS light stays on

A sensor is a good guess, but it's only a guess. You don't want to waste your money on a guess. Assuming this is the yellow "ABS" light, and not the red "Brake" light, the place to start is by having the diagnostic fault code(s) read and recorded. Among a lot of other possibilities, that will tell us if there's an electrical problem with a wheel speed sensor, and which one it is, or if a properly-working sensor is failing to generate a signal. Those are two different problems that will have two different fault codes.

The people at many auto parts stores will read fault codes for you for free, but most can only read codes in the Engine Computer. You may need to visit a mechanic who has a scanner that can access the Anti-Lock Brake Computer. We can figure out where to go next once we know the fault code description and exact fault code number.