The cargo floor, threshold trim, battery covers, anchors, side panels, and other necessary rear trim are removed or loosened to reach the protected module location, taillight signal circuits, and rear electrical compartment without damaging the interior.

The circuit-protected control module is mounted inside the vehicle, and the harness output is routed through a factory rear grommet toward the Stealth Hitch frame. The exterior wiring is kept clear of heat, sharp edges, moving parts, and the bumper fascia, and the pass-through is sealed against moisture.

The passive harness is connected only after the X3’s left-turn, right-turn, brake, and running-light circuits are individually verified. This matters because BMW wire colors and circuit arrangements can vary by model and trim; the vehicle’s signal wires control the powered module rather than carrying the trailer’s full electrical load.

The module ground is secured to an approved chassis ground point and its fused power lead is connected to the proper rear 12-volt battery terminal. Newer X3 models may also contain 48-volt components, so those connections are identified and deliberately avoided.

The 7-way receptacle is assembled in the correct terminal configuration, mounted to the Stealth Hitch frame, and tested for running lights, brake lights, left and right turn signals, 12-volt power, ground, and brake-signal output where applicable. The wiring and module are secured before the trim, fascia, sensors, and taillights are reinstalled; a 7-way-to-4-flat adapter supports smaller trailers and accessories.