Installing a 7-Way Trailer Connector on a 2003 Dodge Ram On my 2004 Dodge Ram (which would be the same as your 2003) the factory trailer connector plug split off from a larger wiring harness on the inboard side of the drivers side frame rail near the rear bumper. There should be a rectangular connector that matches the black connector from the Hopkins Endurance 7-Way Trailer Connector, # HM42190. It4.9/5(3) 2003 Dodge Ram 1500 Trailer Wire Harness and Connector Equip cars, trucks & SUVs with 2003 Dodge Ram 1500 Trailer Wire Harness and Connector from AutoZone. Get Yours Today! We have the best products at the right price.