The present paper addresses an experimental investigation of the dynamic and the control of a longitudinal vortex emanating from the front pillar of a dihedral bluff body corresponding to a simplified geometry of 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 photos provide an overview of the impact of the control on the topology of the vortex flow. Quantitative Stereo-PIV measurements and unsteady forces measurements are used to characterize the interaction between the control and the longitudinal vortex. Controls that change significantly the topology of the vortex core and reduce aerodynamic drag are identified.