A steering actuator system to be mounted to the steering wheel and steering column of a vehicle. The steering actuator system includes a flat baseplate with multiple adjustable sliders. These sliders slide along channel guides within the flat baseplate to accommodate steering wheels of varying sizes. The system includes a gear which mounts below the steering wheel, possibly around the steering column of the vehicle. A steering actuator powered by a motor or some other power source is connected to the gear and when activated can actively steer the vehicle. When connected to a guidance system, the vehicle can automatically be guided and steered via the guidance system and the steering actuator system. This provides a convenient way to add automatic steering to any vehicle with a steering wheel.