script.Parent.MouseButton1Click:Connect(function()
game.Workspace.Map.Baseplate.BrickColor = BrickColor.new(Color3.new(script.Parent.BackgroundColor3))
end)
A simple script that is supposed to turn the baseplate brickcolor to the background color of the button. Instead it just turns black.

2 comments
Instead of making a color3 just set the BrickColor to the BackgroundColor3 itself without wrapping it in a Color3.new
Since Bricks in general just use "BrickColor" through scripts, it tries to turn your buttons RGB color3 numbers into a BrickColor, this just turns out to be black.