The liquid film flow down an oscillating plate was used as a suitable flow configuration to study the dynamic behaviour of electrodiffusion friction probes at large fluctuations. The two-segment probe was flush mounted into the plate wall to measure the fluctuating wall shear rate. The hydrodynamics of the experiment made it possible to adjust both the steady and oscillatory component of the wall shear rate through the operation parameters (flow rate, plate inclination, amplitude and frequency of wall oscillations). The approximate model of the probe dynamic response based on the similarity of concentration profiles at the probe surface was verified. This simple model proved to be able to calculate the instantaneous wall shear rate from the measured current signal even at large flow fluctuations. The analysis of the probe dynamic behaviour under reversing flow conditions provided a new method of the detection of short-time flow reversal. Finally, this method was successfully applied to confirm the existence of a small back flow region located in front of the large solitary waves, which were excited on the surface of a liquid film flowing down an inclined stationary plate.