Recommended 7 Way Wiring for 2015 Mazda CX-9 That Will Use Curt Echo Brake Controller

Question:

Hi, I need to add a brake controller to my 2015 Mazda CX-9 Touring. Currently all I have is a flat four plug. Will I need to buy the following items to be able to control the brakes on my round 7 trailer: https://www.etrailer.com/Wiring/Tow-Ready/30717.html and this: https://www.etrailer.com/Trailer-Brake-Controller/Mazda/CX-9/2015/C51180.html?VehicleID=201583411 For the 4 to 7 adapter, would I leave the blue wire brake controller unplugged. And how about the yellow wire aux 12V? Can I just connect that to 12V also? Thanks for the help, Ill be buying this as soon as I hear back from you

asked by: Wil L

Expert Reply:

You could potentially use the Tow Ready # 30717 to install the 7 way on your 2015 Mazda CX-9, but it's not really a complete kit and requires that you purchase additional 12 gauge wiring # 12-1-1 (sold by the foot), 30amp breaker # PK54530 and heat shrink butt connectors like the # DW05745-5. Typically when installing a 7 way on a vehicle for use with the Curt Echo # C51180 we recommend using the # ETBC7L, which comes with all wiring, hardware, electrical connectors, and breaker. It's a little bit more expensive, but in addition to the wiring components, it also has a 4 way plug integrated that means you're not going to need any sort of additional adapter to tow a trailer with a 4 way plug.

I've linked an installation video of the # ETBC7L kit that you can use as a guide, but you really only need the 12v power connected with the Curt Echo # C51180, so you could leave both the yellow and blue wires connected. If you do need to provide auxiliary power to your trailer, you will want to run a separate wire so as not to create issues where the 12v and aux power are competing for power.