A small control cylinder is placed in a turbulent wake of a 2D bluff body in an effort to control such global features as the drag and the vortex shedding frequency. For certain positions of the control cylinder, large increase of drag fluctuations are recorded. Ensemble averages of PIV acquisitions and pressure measurements at the base of the bluff body reveal a bi-stable wake regime. Long duration hot-wire measurements are used to characterize the states and the transition process. The results show that a stochastic process is responsible for the transitions between the two stable states.