edit : torq should be torx
My 14 horn is acting up again. Cost about €150 to fix at alfa garage last time, them saying the clock spring I think.
Currently, its working intermittently, sometimes horn barely audible or chaging pitch.
might be the horn themselves, not the contacts in the sterring wheel. These are under the bonnet, mounted near the inner wing behind the headlights, left hand side as you stand opening the bonnet.
Can be tested by applying +ve direct and hearing what noise they make.
If I do as you say, and diconnect battery -ve to kill the elctronics and remove sterring wheel airbag, what can I do to fix the contacts, or is it a simple job to just replace it with a new part, with allen key?
And to reinstall, just stick in airbag and reconnect battery?
Yes airbag replacement is the simple job you explained, but it could be the contact plates at fault. IIRC it is an alan key to remove the airbag and a torq drive (pointy star shaped allen key) to remove/adjust the contact plates. Not sure how simple the contact replacement is, but it looks straight forward enough.
On mine one of the spring plastic mounts had broke which meant the horn was always on. It is possible to adjust the contact plates using the four mouting bolts, to compensate for a spring not doing its job (torq drive required).
Ths springs are mounted on plastic collers that can snap, which causes the spring to be no longer fully supported and fall through the contact plate. Spring is not exactly lose, just not pushing against anything. This is what happened on mine, and the fuse blew and the horns packed up as well.