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 bmw e30 fuse box | eBay BMW E30 Fuse Box Red Circuit Board 325i 325is 325ic 325ix 318i 318is ( 004 ) Pre-Owned. $44. Buy It Now. BMW E30 Engine Fuse Box Round C101 Connector Pig Tail 325i 325is 325ic 325ix. Pre-Owned. $29. Buy It Now +$4 shipping. BMW E30 325 318 M3 E24 635 E28 535 528 735 E23 533 Fuse Box w/Cover 1373433.