Hi all you experts. I have a 1988 fiat Panda Sisley.

Electrical problem with the horn

No keys in the ignition. The horn works fine.

Keys in ignition, ignition on, engine running, the horn will not work. I have cleaned the 2 earth hedgehogs and replaced the female connectors. I have checked the earth wire from the battery which appears OK.

No horn, no MOT.

Any ideas please! Thanks.

The horn is a switched earth, so earth will be around the ignition switched area. May be worth finding the earth for it from around the steering column area and re-earthing it to get it to work if time is off the essense before the MOT.

Thanks Most Easterly Panda, I will strip out the steering covers and see if I can identify the earth. May I enquire what you mean by 'a switched earth,?

eltelgulboy said:

Thanks Most Easterly Panda, I will strip out the steering covers and see if I can identify the earth. May I enquire what you mean by 'a switched earth,?

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The switch for the horn is the earth, its operated by earthing the horn rather than putting a live supply to it, the live feed to the horn is always live

Looking at the wiring diagram, the horn earth routes through and in parallel with the left indicator. Have a look around there and make sure the earth connections are clean.

have you cleaned the contacts on the horn? are the spade connectors clean? no green mould on them? this was the problem with mine,worked after clean-up

this may sound odd.. but i have a 1991 sisley but the horn only works when the ignition is on..?

this is rather strange.. could you be getting some kind of reverse voltage back through the horn effectively using the load of all the things running on the ignition as somewhere for power to drain to passing through the horn to make a connection.

when you press the horn with the ignition off, do any lights try to light up very dimly on the dash?

dono, but i just find it odd that the horn works like its on a constant live.. i know for sure talons is on an ignition live as pressing the horn does nothing when theres no key in the ignition..

anyway
this sounds daft, but you see below the coolant tank? theres some earthing points... give them a jiggle.. also do the same to the ones behind the head lamp.

i know its an earth switch but trust me, give it a try. my sisleys horn stopped working once,, moving them earths around fixed it.

worth a shot..

Mine is an '87 4x4 and the horn is in the engine bay behind the right hand side headlight - works both with ignition on and off, my friend's is an '89 4x4 and his horn is behind the front bumper on the left hand side below the headlight and his horn only works with ignition on. Weird, we have come across this issue before trying to get his to work with no ignition, replaced all the wiring and contacts even the steering wheel centre and it didn't change a thing so I'm wondering if like Dragon Man says, there is some kind of reverse voltage going on - or indeed a pair of wires are back to front somewhere?

Has the horn always done this or is it a new Panda self-modification?

Standard horn position is behind the front bumper.