Indiana - Tail light laws

So I bought this LED message board on Amazon the other day, and I plan on installing it on the inside of my truck, facing the rear. It will always be red, not scrolling, and only as bright as my brake lights while not depressed. I've read up on the Indiana Code 9-19-6 and haven't found anything that would prohibit it's use, within those parameters.

I plan on displaying "F*** TRUMP" [profanity removed by moderator] on the display.

Would there be any law you could think of that would prohibit my plans?

Before you reply, according to Cohen v. California, the message itself is perfectly legal.