Provided are electrical harness assemblies and methods of forming such harness assemblies. A harness assembly comprises a conductor trace, comprising a conductor lead with a width-to-thickness ratio of at least 2. This ratio provides for a lower thickness profile and enhances heat transfer from the harness to the environment. In some examples, a conductor trace may be formed from a thin sheet of metal. The same sheet may be used to form other components of the harness. The conductor trace also comprises a connecting end, monolithic with the conductor lead. The width-to-thickness ratio of the connecting end may be less than that of the conductor trace, allowing for the connecting end to be directly mechanically and electrically connected to a connector of the harness assembly. The connecting end may be folded, shaped, slit-rearranged, and the like to reduce its width-to-thickness ratio, which may be close to 1.