4 Pin Wiring Harness | etrailer Quickly and easily install a 4-way and 7-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into OEM tow package wiring harness - no cutting or splicing vehicle's factory tow package wiring harness, which is located at the rear of your vehicle, slightly toward the driver's side. Once installation is Amazon: 4 pin trailer harness CURT 56331 Vehicle-Side Custom 4-Pin Trailer Wiring Harness for Select Chrysler Town and Country, Dodge Caravan, Grand Caravan. 4.8 out of 5 stars 47. $51 $ 51. 46. $9 shipping.