Highway 15 Universal Wiring System - American Autowire Details. Ample lengths of pre-labeled GXL wire make it simple to create custom routing specific to your needs. The Highway 15 is a brute in a small package. Built with the same heavy duty internal components as those used in our Highway 22 panel, it can American Autowire Highway 15 Wiring Harness Kits - Free American Autowire Highway 15 Wiring Harness Kits. American Autowire Highway 15 wiring harness kits are powerful little brutes! Built with the same heavy-duty internal components as the Highway 22s, the small-size Highway 15 panel can easily handle the basic power requirement of your vehicle. The ability to meet high power demands..