A 7-way cable is the cable that runs from your tow vehicle to the Airstream which transmits braking and turning signals. Each time you hitch your tow vehicle you'll need to plug in the 7-way plug and confirm that your travel trailer lights and brake lights are working properly.
This cable can sometimes be referred to as the "7-pin" cable.
Learn more about the Airstream 7-Way cable and vehicle input with the following video.
