You can purchase an inline noise filter for the radio , plus , you can buy some grounding straps and and do some bonding n grounding , like I hear the other guy telling you 👍. I ran one in my Honda . That was 25 years ago though ,, I had 3 different Hondas over the years , hate to be the bearer of bad news , they’re the worst freaking car I ever dealt with as far as Altenator and noise coming through the external speaker 🤬
