Adding 7-Way and Brake Controller to 2017 Audi SQ5
Updated 10/23/2025 | Published 04/03/2025
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Question:
I own a 2017 Audi SQ5 and an Aliner travel trailer with electric brakes requiring a 7-pin harness. I have an appropriate weight-rated hitch installed already. However, there is no wiring or brake controller currently installed. The vehicle only has a computor module plugin for a 4-outlet wiring harness. 1 How can I install a 7-pin trailer harness on this vehicle? 2 Will it work if I first install a 4-pin trailer harness, then utilize a 7-pin upgrade kit? And 3 What are my options for compatable brake controllers? As an aside, Im looking for a system that is independent and does not splice into the cars electrical system. Thanks for your time.
asked by: Mark M
Expert Reply:
Hey Mark! You already have the right idea here. To add a 7-way you will need to start by adding a 4-way. I recommend using the Curt T-Connector Vehicle Wiring Harness # C56404. This plugs into the connection points in the rear cargo area and then you will run a hot lead up to your battery. Once you have your 4-way you can use the # ETBC7 you looked at to upgrade to a 7-way. None of this will require splicing into the vehicle wiring.
For a brake controller I'll give you two options. The first is the Curt Echo Wireless Brake Controller # C51180. This plugs into the 7-way at the rear so you won't have to do any kind of splicing at all. This is controlled via Bluetooth using the app on your phone. However, I do recommend adding a brake controller in the cab. This will be more reliable and easier to control while you're towing. The Redarc Tow-Pro Liberty # RED52VR is definitely my favorite option out of all of the brake controllers.
The Liberty is simple, reliable, and won't take up space in your vehicle. The main unit installs out of sight so only the control knob is visible, giving it an OEM look. The one thing you will have to do is splice into the cold side of the stop light switch. If you're really against it you could install the # RM-751000 and splice into that instead. Any big plans with your Aliner this summer?
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Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
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Robin H.
10/22/2025
Hey Mark, how did the wiring setup go on your Audi SQ5 with the 4-way and ETBC7 kit? I’m curious if you decided to go with the Curt Echo or the Redarc Tow-Pro Liberty for your brake controller. Your update could make it easier for others wiring similar tow setups.