A GNSS control system and method are provided for guiding, navigating and controlling a motive component, such as a tractor, and a working component, such as an implement. A vector position/heading sensor is mounted on the motive component and includes multiple antennas connected to a GNSS receiver. The sensor also includes inertial sensors and a direction sensor, which are connected to a microprocessor of a steering control module (SCM). The SCM can be hot swapped among different vehicles and can interface with their respective original, onboard control systems. The implement can be provided with an optional GNSS antenna, receiver or both, and can be guided independently of the motive component. The SCM can be preprogrammed to guide the vehicle over a field in operating modes including straight line, contour, concentric circle and point+direction. A spray boom with multiple nozzles can be installed on the implement and the nozzles can be independently activated based upon a location of the implement as determined from a log of GNSS data.