What Adapter do I Need to Go From a 7 Blade to a 4 Flat on My 2016 Toyota Tacoma?

Updated 03/17/2026 | Published 03/16/2026

Question:

I have a Toyota Tacoma with 7pin circular connector wire harness which supplied the native pwm driven signals for brakes, running lights, etc. I need to convert 7pin to 4pin and pwm to 12 constant to use with an older trailer. Can you please confirm the products I need to do this with? I think it’s a curt converter and then a 7 to 4 pin pass through adapter like PT791-89040 but would like an expert to confirm.

asked by: William G

Expert Reply:

Hello William,

Great question, and you’re absolutely thinking about this the right way wanting to make sure everything plays nicely before plugging in.

The good news is that since your Tacoma already has a factory-style 7-way, you do not need a separate PWM-to-12V converter. The truck’s 7-way is already designed to output trailer-ready lighting signals, so you are not going to risk confusing the vehicle electronics or damaging anything by using it.

For your setup, a simple 7-way to 4-way adapter is the correct and complete solution, and the TowSmart 7-Way to 4-Flat Adapter # TS98RR will work perfectly. It is truly plug-and-play. Just connect it at the back of the truck and you will have the standard 4-flat output your older trailer needs. No extra modules, no splicing, and nothing additional to mount or protect from the elements.

So you can confidently skip the Curt converter. That is only needed when wiring directly into a vehicle’s tail lights, not when you already have a functioning 7-way.

As long as your 7-way is working properly, this will be a clean, reliable setup that you can plug in and forget about.

What kind of trailer are you looking to tow that has a 4 flat? Small utility, boat trailer, etc?