Upgrading A 4-Flat On A 2017 Toyota Yaris To A 7-Way  

Question:

Expert Reply:

Hi Pat!

I do have an option for you, but there isn't anything that I am aware of that will actuate trailer brakes off a 4-flat. You will need to upgrade to a 7-way on your 2017 Yaris. But having the 4-flat already does make the process easier, so that's a plus!

With that said, you are going to want the 7-Way RV Upgrade Kit for Trailer Brake Controller Installation - 12 Gauge Wires # ETBC7L. This will piggyback off your 4-flat and has all the other wiring needed to get a wireless brake controller working. I included a diagram that shows what you will need to do as well.

Once that is installed, you can use something like the Curt Echo Wireless Brake Controller - 7-Way Plug-in w/ Bluetooth App - Up to 2 Axles - Proportional # C51180. It uses your smartphone to set it up and has the manual override button built into the app you will need to download. Now I will admit to not being a fan of that as I prefer to use my phone as a phone, so I would also grab the Manual Override Button for Curt Echo Brake Controller # C83HR to bypass the app for that function.

If you prefer to go with a less expensive hardwired option, just let me know and I can put a kit together for you. You will need a different 7-way upgrade kit that technically costs a little more (specifically the # ETBC7), but the brake controllers we have will be quite a bit less expensive (like the Tekonsha Prodigy P3 # 90195 you were looking at).

And out of curiosity, what kind of camper is it?

expert reply by: Lazer S

0

ETBC7L Diagram
(click to enlarge)

Pat K.

10/30/2025

Hi Lazer, The camper is an Aliner Ascape ST. I was expecting to purchase something lighter but I came across a deal I couldn't pass up, since it's closer to the upper limit of what my car can tow I've been scrambling to get it ready for the braking system. I decided to have an auto electric shop handle the upgrade, I'm skilled with wiring but not on ground vehicles. If you could send over the part info for the hard wired system in case I need to order it, that'd be greatly appreciated. Thank you for taking the time to reply!

Lazer S.

10/30/2025

@PatK That's a cool little camper! I bet you are going to have some fun with it. ^__^ For a hardwired option, you will want the # ETBC7 1-way upgrade kit. It has another wire and a few other pieces included to get a hardwired brake controller up and running. As to the controller, the Tekonsha Prodigy P3 # 90195 is the best controller on the market and will work extremely well, but it will likely be a bit overkill for your set up. I would go with something like the Tekonsha Voyager Trailer Brake Controller - 1 to 4 Axles - Proportional # 39510. It's less expensive, but will absolutely get the job done. It's easy to use and set up, and you can either cut the plug part off for the hardwire or also grab the # 20127 pigtail so you can remove the controller if/when you don't need to have it in your car.