Only have wiring diagram for 3.7 Roadster but that has no relays for horn or headlights. The common denominator seems to be stalk switch you changed and/or wiring/connectors from steering wheel, not relays or fuses.

Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone