‘‘aftermarket’’ radio ?
All bets are off now concerning anything Honda.
Look for an amplifier , they usually have their own internal fuse you need to check.
The radio head may also have its own fuse in the rear of the unit.
Also check for a separate circuit that may have been tapped for either the head or an amp and see if that has a fuse in need of tlc.
Here’s another thing about aftermarket sound and second owners ;
VERY , VERY often the first owner will REMOVE their precious high dollar amplifiers and maybe even their super-duper speakers too, and leave the next owner holding the bag.
-----check the entire system for signs of MISSING components. ( usually in the trunk )-------
If components have been removed you can opt to wire the head direct to speakers in the simple set up the head could have without the hotshot system.
Next step , take it to a sound system specialty shop ( not a Honda dealer ).