Symptoms of a Bad Ignition Relay, Function & Location The ignition relay is situated in the fuse box found in the engine bay. When you locate the fuse box, open it and find the mapping on top of its lid. The key will tell you the exact position of the ignition relay as well as other relays and fuses. Once you have located the relay, gently pull on it to remove it from the fuse box. Fuse and relay box diagram BMW 3 E46 (30A) Ignition coils-320i with MS43/325i/330i. F2 (30A) Engine control module (ECM), reversing lamp/s relay, transmission control module (TCM) – 316i/318i. F3 Fuse box in the glove compartment BMW E46. Open the glove compartment and turn the two white quick-release fasteners outward.