Does 4-Flat to 5-Flat Adapter Require Splicing

Question:

Is there an easier way to use the adapter on my 2018 Highlander w/o rewiring?

asked by: Deb

Expert Reply:

Each of the vehicle-side 4-Pole to 5-Pole Trailer Wiring Adapters such as the Tow Ready # 20036 will require you to spice the blue wire of the adapter into the reverse light wire on your 2018 Toyota Highlander. It is not difficult to accomplish because this kit does come with a quick splice connector and I have also linked a video for you which shows this adapter being installed on a Highlander. You will need a circuit tester like # PTW2979 to find the reverse light signal on your Highlander.

The reason you need to splice into your reverse lights is because a 5-flat has an additional wire which is used to disengage the hydraulic trailer coupler when the vehicle is reversing; tapping into the reverse lights is what allows this to function.

expert reply by: Kyle S