Had a problem in the past with the horn not working, then it's all ok again when the ignition is turned off, then back on. When it stopped working before if pressing the horn in (without it sounding) the radio volume would increase, weird! Now when this has happened before switching the ignition off and on again seems to clear the fault. Now it doesn't clear at all just no horn but the radio volume increase still occurs when pressing the horn.
All other controls work normally on the steering wheel except the horn.
Anyone else had this problem, could it be an earthing fault due to the weird volume increase when the horn is pressed, or some other contact faulty?
BTW '06' plate Signum