Recommended Way to Re-Wire a Boat Trailer with a 7-Way Plug

Updated 10/27/2014 | Published 10/26/2014

Products Featured in This Question

Hopkins Heavy-Duty Trailer Coiled Wire Adapter 7-Way to 5-Way Flat with Nite-Glow

(55)

$50.87

Dielectric Grease for Electrical Connectors, 2 oz.

(1459)

$10.96

Trailer Wiring Junction Box

(814)

$27.58

Hopkins 7-Way RV Style Connector with Molded Cable - Trailer End - 8' Long - RV Standard

(907)

$46.90

LCD Digital Circuit Tester

(23)

$27.22

Question:

I have a shorlander boat trailer with a 5 way connection. I have a marine 5 way to 7 way adapter I was told it is different than a standard 5 way - the extra pin is for reverse which deactivates the surge brakes..the wire is too short for my new vehicle. Will this have the correct 5 way adapter for my trailer.

asked by: Chris A

Expert Reply:

The adapter will work but it's more of a short-term solution because of the potential corrosion issues in the future not to mention when you introduce additional connection points problems can arise.

I would test the reverse lockout (purple or blue wire) with a circuit tester with the 7-Way center pin. If that works you are good.

I would recommend rewiring the trailer with a 7-Way plug because it will prove to be more reliable than using an adapter. I would start with a trailer junction box # 38656 as it provides an easy way to connect wires from the trailer connector to the trailer wiring. You will also need a trailer connector RV style 7-Way blade # H20046 with 8-foot lead. You will then test the wiring with a circuit tester such as # PTW2992 to confirm each one's function as you make your connections.

Typically, the 5-Way Flat is used for trailers with surge brakes or hydraulic brakes. The additional wire is tapped into the backup lights to disengage the hydraulic trailer coupler (actuator) when the vehicle is reversing, thus turning off the trailer's brakes.

I would recommend dielectric grease such as # 11755 is used to keep moisture out of the electrical connections on your wiring and to inhibit corrosion.

I have included a couple FAQ's and installation videos for you as well.