E30 Fuse Box Diagram, High Resolution, Printable | E30 Gruppe The fuse box is where you want to start with many problems you may encounter with your E30. While relays rarely go bad, it’s still very possible. One thing you can always do to test a relay easily is if your Horn is working, put that relay from K2 into the Low Beam K4, or other slot which you’re trying to get working. Download the E30 fuseAuthor: Tone E30 M3 Fuse Box Diagram - e30sport E30 M3 owner and enthusiast Jake Larson has gone to the trouble of creating this very useful "Fuse Box Diagram" for our cars. If you are needing to dig into the fuse box area to do any electrical work then these diagrams will proove quite valuable. BMW E30 Informational and DIY Resource! | E30 Gruppe E30 DIY, Guides, Resources, Specifications, and more! Explore some projects you can do with your E30 whether it's regular maintenance or major upgrades!