Wiring Adapters to Connect 4-Pole and 7-Way Type Wiring

Question:

I have a 4 flat regular trailer plug I need to hook up to a 7 blade plug.hiw do you do this.can you show me a diagram

asked by: Moreland

Expert Reply:

We can help you with wiring adapters, and also a wiring guide, for your vehicle and trailer that have different wiring setups.

If the vehicle has 7-way wiring and the trailer has 4-pole flat wiring you can use an adapter like Pollak part # PK12716 or Curt part # C35FR which allow connecting a 4-pole trailer plug to a vehicle with a 7-way.

If instead the vehicle has a 4-pole setup and the trailer has a 7-way harness then you can use adapter part # 37185 which plugs in at the vehicle and provides a 7-way socket. In this case using the adapter will only allow the 4-pole wiring signals to reach the trailer unless you also connect the additional circuits using the adapter's pigtail leads.

If you want to convert a vehicle's 4-pole flat wiring to a fully-functioning 7-way setup, with those three additional circuits all active, then you can use 7-way install kit # ETBC7.

You can refer to the linked article to see all of the different formats of connectors and the usual assignment of functions on each of the contacts. I also included a diagram of a 7-way vehicle socket that shows the usual configuration of functions and pins.