An electronic system generally includes a flatwire electronic site and a flatwire bus electronically connecting the flatwire electronic site to an electronic device in the engine compartment. The flatwire electronic site has a flexible substrate with electronic components attached to the substrate for operation of the electronic device. The flatwire electronic site is mounted to the passenger site of the bulkhead for thermal cooling as well as protection from the harsh environment of the engine compartment. The bulkhead has an aperture sized to allow the flatwire bus to pass through the bulkhead into the engine compartment. By utilizing a flatwire bus, this aperture is small in size and the integrity of the bulkhead is improved.