Join Date: May 2010
Location: Williamsburg, VA
Sometimes lights require much more amperage (hence bigger wire, more power) than tyical switches are usually made to handle. Rather than run from the battery into the cab, thru a switch and back out to a light you use a relay. It only takes a very low current to run the relay, so your relay switch leg goes from the cab and thru the relay. That way your higher power wire is confined and you don't overload your switch. As others said, also use a fuse to prevent melting things! Whether inline, or thru a fuse block doesn't really matter, just protect it. If you need assistance on how to do it the link above has all the info you need!