Recommended Trailer Wiring Harness for 2016 Chevy Express Recommended Trailer Wiring Harness for 2016 Chevy Express Van . Question: I have a 2016 Chevy Express 3500. I was told the wiring is there for a trailer, but I dont see any. Can you direct me where to look? My van didnt come with the tow package, as I was told the only difference was the hitch which I purchased from you. Thanks4.9/5(1) Chevrolet Express Van Trailer Wiring | etrailer Trailer Wiring Harness Installation - 2014 Chevrolet Express Van. Speaker 1: Today on our 2014 Chevy Express Van we're going to be taking a look at and showing you how to install the Hopkins Plug In Simple Vehicle Wiring Harness with Four Pole Flat Trailer Connector, part number 31345.