Need help with locating the fuse and relay for the horn on a 2004 Mazda Demio model DBA-DY5W

[Lahoo73]

I have looked under the bonnet and near drivers side panel and behind glove box and can not see any fuses or relays for the horn. Also no mention on fuse diagram for this model, have checked the wire connected to the horn and tested the horn on a work bench which are both fine so guessing it's a power supply problem. So any help would be greatly appreciated.