The present disclosure refers to a retainer assembly adapted to be installed between a base assembly of an exterior rear view device and a vehicle to which the exterior rear view device is mounted, the retainer assembly, comprising a retainer means adapted to be mounted on one side to a door attachment portion of a base frame of the base assembly and on the opposite side to a door panel of the vehicle, wherein the retainer means is provided with at least one opening for allowing at least one datum structural element of the door attachment portion of the base frame to pass thereto, and at least one guiding projection and/or at least one guiding channel portion for providing at least part of a guiding channel for routing and/or guiding at least one harness from the vehicle to an electric component of the rear view device, and/or at least one sealing portion for covering at least a portion of the at least one harness. It also refers to a exterior rear view device with such a retainer assembly, a method for assembling such a rear view device and a vehicle with such a rear view device.