Horn does not work - but with power to the horn = OK. just when the steering wheel is pushed = not working

I would check to see if you are getting power to the horn itself before removing the steering wheel. Check for power at the horn using a 12V circuit light test or a multi meter. If you are not getting power to the horn ensure the fuse is not blown or the horn itself is not malfunctioning. I am not familiar enough with a Ducato to walk you through a steering wheel removal. I would start by disabling the airbag circuit before anything else to prevent injury. If in doubt leave that to a professional. Good Luck.

the horn have fuse and relay in engine fuse compartment.inspect all the fuses. in your owners manual is the location of the fuse and relay. if OK, one person push the horn and other check power to the horn.if no power swap the relay with other one for test.if you SRS light is ON and the horn does't work suspect the clock spring(soft connection below the steering wheel to column)
good luck

I would check for the following:
1. Fuse
2. Relay
3. Wiring
4. Horn itself (disconnect it from the car, use a wire to connect to horn and tap it directly to the battery, if it horns then it is ok, if not probably need a replacement.
5. Push button on the steering wheel
6. Rotor contact on the steering wheel

The likely cause of this is a defective rotating printed circuit coiled contact under the steering wheel, it is referred to as the "clock-spring" contact coil. To replace it requires the very dangerous airbag system be disarmed and the steering wheel removed, it is directly under the wheel. Before replacing any parts have the problem diagnosed to confirmed my guess work.

Un plug horn connect horn to another 12 volt power source, if it works then the problem is the horn button located in the steering wheel assembley

if the steering wheel clicks when you push on the horn then the wiring from the horn pad out to the horn is good.if it clicked before you replaced the parts then you didn`t have to replace them.check the horn at the horn,with someone pushing on the horn pad tap the horn to see if it will try to work if so then the horn needs to be replaced if not then run a power wire from the battery positive to the connector at the horn if the horn works again the horn needs replacing.

Generally the steering wheel boss switch does not wear out (the horn is not over used!). I would check the fuses and then the relay and if they look OK check the wiring form the relay to the horns for continuity. Use a voltmeter to check that voltage is being supplied to the relay when the horn switch is pressed. Then check that voltage is being output by the relay in response to this voltage input. If this all looks OK then there is some kind of break in the wiring to the horn unit

I would start by removing your steering wheel and make sure that you have power there. If so you have a bad ground. Horns work when you push the center of the steering wheel it will contact a ground a the horn will sound.

Probably the switch in the steering wheel, or fuse, but usually horn fuse works other things too such as cig lighter or radio. If everything else is working fine, then to troubleshoot you'll need a testlight. I would start with the wiring harness where the steering collumn plugs in and decipher which wire is the horn wire. Put the test light clip on +power, then check the wires on the collumn side one by one, pushing the horn button on each one. The horn switch is the wire that makes the light blink when you push the button. If you try all the wires and none make the light blink, then its probably a problem with the horn switch in the s. wheel. Does it have an after market steering wheel? Because aftermarket wheels often have crappy horn switches in them. Also could be a horn relay if it has one. If you listen carfully while pushing the horn, you should hear the relay faint clicking. If you hear this, then the switch is working, but the relay might not be. Follow the sound to find it if you hear it. Test all sides of the relay with your light. Should get power constant on one term, and the other two should light when the horn button is pushed. Hope this helps. Cheers.

If your Air Bag light light is aluminated and The Cruise Control does not Work then the Problem is in the "CLOCK SPRING" this Component is Located Under the Steering Wheel and it requires the Steering Wheel to Be Removed.You Must have Complete Instructions on this Procedure or Injury Can Be the result.