Prius 2010 - Horn not working

[roks]

Hi All, 

My brother has a 2010 Prius, horn volume gradually went down and even died. I got him to do steering wheel, lock left and right and horn was still not working.

Today I had a look in the fuse box, the 10A fuse s/horn was fine, there was also a missing relay marked s/horn, I borrowed the fan relay and tested the horn it wasn't working, then I got him to lock steering wheel left and right and it worked on the right lock.

The horn is still working in all position, I've move the replay back to the Fan position.

Is there supposed to be a relay in s/horn?

What's the likely cause of the horn not working in the 1st place?

Thanks in advance.

[Red_Corolla]

Doesn't sound like a missing relay if you can make it work without. Perhaps the one you found is for an optional secondary device? Have a look to see if you can find another horn relay.

If it's getting affected by the position of the steering wheel then I would say it's almost certainly the clock spring or slip ring arrangement behind the wheel making a poor contact.

[roks]

Thanks @Red_Corolla, I come across another post elsewhere, something about 'coil wire' on the steering column. Will see how expensive and difficult it is to change.

[roks]

Update: Replaced the clock spring/spiral cable, 30min, it wasn't too difficult, all working now.

Thanks