Recommended Redarc Tow-Pro Liberty Brake Controller for a 2020 Subaru Ascent w/ the Tow Package  

The universal wiring harness worked great. I would recommend soldering the connections instead of relying on crimp connections.

The universal harness recommended worked fine for my application as well. Wiring info for the specific vehicle integrated exactly with the harness.

Joe, I have a 2021 Ascent, I added a Subaru tow hitch from the dealer and received an adapter cord with it in case I wanted to add a controller in the future. Later I did add a Redarc Tow Pro Liberty controller. I didn't use a mounting panel but elected instead to mount it in the dash, lower left by the steering column. The control knob is small enough to be unobtrusive and looks factory installed. The cord that came with the tow hitch worked to hook the controller up, but finding the plug in the harness wasn't obvious or exactly where I expected it to be according to videos I saw on Youtube but more tucked away, rotated upward on top and harder to reach). Once I located it and plugged the cable in it was relatively simple to run the wires to the controller. I zip tied the controller securely onto a strong support bracket that wouldn't move when in motion and drilled a hole for the knob where I could reach it. None of this was easy to get to behind the dash and required some finagling and cursing to get it all in order (watch out for sharp edges on support brackets, some blood may have been spilled also). I've been using it for a couple of years and once I figured out where to set the knob (on 4.5) it's been working great. I tow an InTech Sol Dawn Rover, gross weight 3500# and it's performed smoothly, even in panic stops. It's possible to inadvertently change the knob setting getting in and out so I've developed the habit of checking that each time I enter when towing. It's important to keep the trailer brakes adjusted, something you can do yourself. I had few photos but can't find them readily and may have deleted them after this much time has passed. I'd suggest Youtube for getting a general feel for the installation.