I am trying to make it so people can control their car lights in my game. I don't need a script from you, I just am wondering how I could set it up so that a car is a property of a player.
Hmm. Well, in each car in the game, you could have a StringValue and it's name/value could be the Player's name. In the Button, you'll have it use the for loop to check every car to see if it has that value with the Player's name, then it'd toggle that.
Alternatively, you could change the model's name to say p.Name.."'s car"
and have the button find it by using a = game.Workspace:findFirstChild(game.Players.LocalPlayer.Name.."'s car")