Car glass makes interior vanish?

I'm not sure why but the windshield makes the interior vanishThis image is no longer available because of changes to Discord's CDN

EDIT:This does replace the fire truck but it works fine in game besides the windshield with using the bart_v.con file but i dont think that has anything to do with it

Make sure the windshield is at the bottom of the hierarchy in the vehicle mesh, like this.