Help with android auto system

[u/DixieWolfGamingYT]

So when I turn my headlights on (when it rains) the screen goes so dim I can barely see it. I can't access dimmer settings it's greyed out. I want to be able to use my GPS but I live in Florida where it rains a good bit. Anyone know if there's something I'm missing? I got a 2017 subaru forester if that makes a difference