There are a couple of differences between the wiring harnesses for your 2016 Ram ProMaster. The biggest difference is the technology used. The Curt # C56270 uses what is called Surface-Mount Technology. Essentially what this does is almost eliminate the draw on tail light circuits. which traditionally draw the most amps. The Curt harness also has a maximum amperage of 7.5 amps per circuit on the stop and turn lights, while the Tekonsha # 118719 has a max amperage of 4.2 amps per circuit.... view full answer...