The Curt T-Connector Vehicle Wiring Harness # C56259 is designed to work with your 2021 Subaru WRX, but if you've had it that long and reinstalled it that many times I wonder if the wiring is just worn out. Here's what I recommend doing to determine if the issue is compatibility or just the wiring itself:
Connect all of the wiring as the instructions call for it, and then use a circuit tester to see if the correct signals are on the correct wires prior to the converter box. Then do the... view full answer...
The exhaust rattle you're getting with the EcoHitch Trailer Hitch Receiver # 306-X7257 in place on your Subaru WRX actually isn't too uncommon and there are a few simple ways to resolve this. We actually have a great article dedicated to exact this subject, which I have attached below.
The easiest solution is to simply bend the exhaust hanger a bit to provide more clearance between it and the hitch. You can just use a pair of vice grips or some pliers to manipulate the hangers so you... view full answer...
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