I am trying to use proper REST urls with MVC. To do that I switched default Routing from:
{controller}/{action}/{id}
Try passing in new (empty) RouteValueDictionary in your controller
return RedirectToAction("Search", new System.Web.Routing.RouteValueDictionary{});
And here:
Html.ActionLink("Approve", "Approve", new { Id = 23})
I don't even know how can it pick up the Customer controller, since you are not specifying it anywhere. Try providing both controller and action to ActionLink helper.