14 Each instrument has its own sender connection (where applicable), which means each should have a distinctive color code. As you establish your own color-coding, write it down. Sometimes with aftermarket harnesses, color-coding isn’t always what we’d like to see. We suggest looking to Painless Performance for your instrument harness and following the Painless color-coding. Gil has done a nice job of organizing his custom harness with clean connections and zip-tie wraps.