Another question is to indicate what it is that the indicators do not do? Do they fail to light up, or indicate full all of the time, or .....? Waste tank indicators are notorious for indicating full when they are not and it may not have anything to do with lightning. If none of them light up, or operate at all, there is a good chance that the problem is a bad ground lead. It is unlikely that the lightning strike was the cause since the tank indicators are 12V-dc and that comes from inside your RV.
Good travelin! ......Kirk