The present paper addresses an experimental investigation of the dynamics and the control of a longitudinal vortex emanating from the front pillar of a dihedral bluff body simulating an automotive vehicle. The control system is based on a thin rectangular slot located along the lateral edge of the windscreen and provides steady suction or blowing normal to the lateral face of the geometry. Qualitative results obtained with dye visualizations and Schlieren photography provides an overview of the impact of the control on the topology of the vortex flow. Quantitative Stereo-PIV measurements and unsteady forces measurements allow to characterize the strong interaction between the control and the longitudinal vortex .Solutions capable of preventing vortex breakdown and reducing aerodynamic drag are identified.