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. The fuse is intact. From the horn push contacts at the steering column 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

:bang: :bang: :bang:

i had a similar prob on my sisters punto but it was just that the horn switch didnt have a good connection to the wire from the column., if thats not it just run a new wire to the horn itsself.,.,

vtec said:

i had a similar prob on my sisters punto but it was just that the horn switch didnt have a good connection to the wire from the column., if thats not it just run a new wire to the horn itsself.,.,

Click to expand...

Hi, thanks for the reply. The connections test out OK. How did you get the new wire up to the column horn switch?

regards,

David

you cant get a new wire all the way up the the steering wheel as it obviously has a slider contact which enables you to turn the wheel without damaging the wires, but you can tap into the wire just below the stearing head(behind the ignition switch), join the new wire here and if that doesnt work then it must be the slider contact that is causing the problem. you'll need to remove the steering wheel to get to this,.,.

vtec said:

you cant get a new wire all the way up the the steering wheel as it obviously has a slider contact which enables you to turn the wheel without damaging the wires, but you can tap into the wire just below the stearing head(behind the ignition switch), join the new wire here and if that doesnt work then it must be the slider contact that is causing the problem. you'll need to remove the steering wheel to get to this,.,.

Click to expand...

Thanks, I'll have another look later in the week. I think that the slider must be faulty to some extent as the resistance is higher than I would expect. I can't figure out how I'm getting a voltage of around 7.8V without the horn button being pressed. Whatever's causing this is probably preventing the relay coil energising when the horn is pressed. Do you know if the live feed comes up from the relay circuit in the engine bay? If it does then I'll try bypassing straight from there up to where you suggest,

regards

David

im not sure but i think it comes from the interior fuse box.,. easiest way to find out is to open the fuse box and look at the diagram to see if there is a horn symbol there.,.,

vtec said:

im not sure but i think it comes from the interior fuse box.,. easiest way to find out is to open the fuse box and look at the diagram to see if there is a horn symbol there.,.,

Click to expand...

thanks, M8 for all your advice............