Just an fyi on third gen I know about. The third light on the outside back of the cab has an issue, on the 2016 mods. The install has either left it leaking or with a broken mount. It’s not a real cheap fix to have it done but it does exist on a lot of the trucks. If it will pull away from the body or move at all, you have the issue. Any continuous water infiltration will cause the interior to smell like dirty wet socks or a locker room…..