Fiat Punto horn fault

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

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More than likely it's the circular box thing that you metioned. There's a coil of flex wire inside with horn and airbag connections. You won't get a proper reading on the multimeter with the relay removed, so the voltages you mentioned don't really mean anything. Try and find the horn wire where it comes out from the steering wheel at the steering column. There should be two wires for airbag and two for horn. Fit horn relay, turn on ignition and join the two horn wires. If the horn works, then fault is in wheel if not you'll have to look further.

JOhn

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John

Thanks, John I'll give that a go. I've ordered a Haynes manual so that I can see the wiring diagram. I'm worried that I may activate the airbag!

regards,

David

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Just disconnect the airbag before you go near it. All airbag wiring is sheated in yellow or orange. There should be a connector on the steering coumn.

Reply to
John

Thanks, John. I'll have a go over this weekend. I'll let you know how it goes........

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