how do you replace a speaker that's under the airbag panel.

Hello, This may be accessible through the glove box, if you remove it from the dash. Behind the glove box there is not a ton of room to work, but it is better than removing the dash. I've never pulled a dash speaker out of a Sonic, and I don't even show one there. I see that there are tiny high speakers between the windshield and the passenger window (A-pillar), but that should not be difficult at all if that is the replacement you are discussing. Let me know, thanks.