Wheel speed sensors are often called ABS sensors. You'll find them mounted on the axles of all ABS equipped vehicles on your wheel hubs, near the brake rotors. The ABS sensor is a vital part of the braking system. Without a working ABS wheel speed sensor, the ABS system will fail to work properly. Resulting in a ABS Light on your Dash and loss of your Antilock Brake System. Fit 07-08 Mercedes-Benz CL500/07-10 Mercedes-Benz CL550 /07-10 Mercedes-Benz CL600/08-10 Mercedes-Benz CL63 AMG/08-10 Mercedes-Benz CL65 AMG/10 Mercedes-Benz S400/09 Mercedes-Benz S450/08-09 Mercedes-Benz S500/07-10 Mercedes-Benz S550/07-10 Mercedes-Benz S600/08-10 Mercedes-Benz S63 AMG/07-10 Mercedes-Benz S65 AMG