460 minibus horn failure

[Rob62]

Hi all, I have a 2016 2.2L minibus mid way through a camper conversion. A few weeks ago i got a call that the alarm was sounding (bus is at my parents house). When I got there it wasn’t the alarm sounding but the horn. The big heavy steering wheel lock had slipped and was pressing on the horn, it had been blowing for about 15-20 mins, so an easy fix...just reposition the steering lock and all ok.. A couple of days later I went out for a run and tried to blow the horn at a mate of mine walking down the road.... but it didn’t work. I have tried to fix it this weekend but have a few questions. Firstly I checked the fuse which was ok. I can hear something clicking when I press the horn button, also all the other buttons on the steering wheel work so I presume that rules out the clock spring? I removed the horn to check for power at the plug but there is no power when the horn is pressed (2 pin plug). I also put 12v across the two terminals of the horn but it didn’t make a sound.. I haven’t checked the relay yet and i guess that could be faulty but what are the chances of having a faulty relay and a faulty horn? Am I doing something wrong? Any help appreciated, cheers. Rob.