Where does the signal go from the speed sensor on the rear differential?

The signal from the speed sensor on the rear differential typically goes to the vehicle's Engine Control Unit (ECU) or Powertrain Control Module (PCM). This information is used to calculate vehicle speed, which can affect various systems such as transmission shift points, antilock braking, and traction control. Additionally, the signal may also be sent to the speedometer to provide the driver with real-time speed information.