Need a perspective: I put a Stebel Compact Airhorn on my F800GS last night. Horn worked...once...then caused the CANBUS to shut down the aux plug circuit. Why? CANBUS reset and the horn worked again...once. An overly simplified diagram: A word picture of the circuit: 1- BMW accessory plug above the battery connects to 2-Relay connects to 3a- battery and 3b- AP1 Fuse Panel connects to 4-Horn Relay connects to 5a- OEM horn and 5b- Stebel Compact Why would the horn shut down the AP1. Obviously the horn is overpowering the CANBUS, but why. It is isolated from it by two relays. I don't understand. I've used this set up on my R1200GSA with no issues. AP1 is also running the Zumo450 and Starcom1 Advance. They worked fine for a week prior to my adding the horn. They still work fine since I've disabled the horn circuit pending further experimentation. Help is requested.