Hello, I'm Danny.
It's possible when the aftermarket radio was installed they could have spliced incorrect wires or hook things up incorrectly. Upon re-installation of the factory radio it possible that the wiring still remains incorrectly installed. I would suggest removing the factory radio to inspect the radio wiring circuit to inspect and see what is installed correctly or if further repairs to the wiring is needed. Here is a tutorial showing how to test electrical wiring:
https://www.2carpros.com/articles/how-to-check-wiring
I've attached the wiring diagram below of the radio electrical circuits for your Honda. I've cut the picture into 3 pieces so you can view larger. Hope this helps and thanks for using 2CarPros.
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Sunday, August 29th, 2021 AT 9:13 PM