Recommendation to Connect 4-Way on Tow Vehicle to 7-Way Connector on Boat Trailer

Question:

Hello, I wanted to know what wiring adapter would work best for me. My boat trailer has a 7 round plug on it and one of the vehicles I use for towing only has a 4 flat plug. Is there an adapter that would would allow me to connect them together. Thanks

asked by: Mike S

Helpful Expert Reply:

If you only need the 7-Way connector on your tow vehicle to power the basic signal lights on the boat trailer (the boat trailer does not have electric brakes), then you can simply use the Tow Ready Adapter # 30717. This will plug right into the existing 4-Way on your vehicle to provide a 7-Way to connect with the trailer. The remaining wires from the adapter are blue for brake output, black for 12V power, yellow for reverse light or reverse lockout on trailer brakes, and white for ground. If these wires are not needed, they can simply be tied off and not used.

If you instead need a fully functional 7-Way on the vehicle (your trailer does have electric brakes or you need the additional functions other than basic signal lights), a better option is to use the Universal Wiring Kit # ETBC7. This kit will provide you with the necessary 7-Way connector but it also includes everything needed to wire the vehicle up to make it fully functional, including ring terminals for battery hookup, quick-splice connectors, and 25 foot long duplex wire. I have attached a great article that details the installation steps for this kit that you might find helpful.

Then, if the trailer is indeed equipped with electric brake assemblies, you will also need a brake controller. For this, I highly recommend the Tekonsha Prodigy P3 # 90195. This is an excellent, proportional controller that will activate the trailer brakes at the same time and with the same intensity that you apply to them in your tow vehicle. It features an easy to read display, storable settings, and continuous diagnostics to alert you to any potential issues.

expert reply by: Chris R