The coupling current-losses of a full size, fusion dedicated Nb3Sn cable-in-conduit superconductor are measured as a function of the transverse load in the SULTAN III test facility. Applying a broad range of transport current (up to 56 kA) and background field (up to 12.1 T), the change of the transverse resistance is observed through the shift of the 0-crossing in the pick-up coil voltage. Despite the difficulty to extract useful information from the signal, the role of the strand Cr plating as resistive barrier is experimentally assessed under operating conditions. The friction factor of the conductor is also evaluated front pressure drop measurements.