Where on the rear differential is abs sensor a 1999 dodge ram 1500?

On a 1999 Dodge Ram 1500, the ABS sensor for the rear differential is typically located on the differential cover itself. It's usually mounted to a threaded boss or bracket on the cover, near the axle tubes. It's a relatively small sensor with a wire harness leading away from it.

However, there's no guarantee of its exact position without visual inspection. The precise location might vary slightly depending on the specific rear axle configuration (e.g., 8.25" or 9.25"). It's best to consult a repair manual specific to your truck's year and axle type for a diagram. A diagram will usually show where this sensor and other components are located.