Hey Martin, the trailer wiring I would recommend is the Tekonsha kit part # 118553 for your 2014 Nissan NV 2500 as it has a simpler install and has the most reliable converter box. view full answer...
If you already have a 4-Way # 118553 on your 2021 Nissan NV 2500 then you can use our 7-Way Install Kit # ETBC7. This kit includes the wiring which will also allow you to install the Tekonsha Prodigy P2 Trailer Brake Controller # 90195 to control electric trailer brakes. view full answer...