My sons 2003 Fiat Punto Active 60 8V  failed its first MOT 'cos the horn has
suddenly stopped working. I've checked out most of the circuit and need some
advice. The horn push is working fine, and the horn itself  works when I
short across the power side contacts at the relay base. From the steering
column horn push contacts back to the relay base I have a continuous circuit
when checking using my multimeter although the resistance is high at 38 Ohms
(or 60 swapping the leads around). When the battery is connected I find that
the horn push circuit has 7.8Volts across the relay base connections whilst
the button is not pressed! When I press the horn button the voltage
increases to 11.8Volts (relay not connected). I have checked the relay
itself and it appears OK and have tried swapping it.
   I suspect that there is another "component" or device in the circuit
causing the 7.8V to appear which is creating the fault.
One further thing, I see that the horn push button wiring disappears within
the steering column into a circular box directly underneath the airbag/horn
circuitry. This box carries the stalks for the wipers indicators and has a
number (735337940) on it. Googling tells me its a "PUNTO FL . 2003 1242 8V
CF3 SOUND ACTIVE DYNAMIC" whatever that is! Could this be creating the
fault?

Any advice on what may be causing the problem and how to repair it would be
appreciated,

regards,

David