Horns not working

[Tomtit]

The horns have stopped working. The fuses and relay are OK, and the horns work when given a 12 volt supply from the Battery. My next step is to check the horn switch under the steering wheel pad for continuity.

I have a copy of the manual for the USA market, but the connector on my car (a British 52 plate LS430) is different and the wiring colours do not correspond. I have attached a copy of the manual page. The second image down shows the connector with 6 segments in a horizontal line. (It may be the first image ; the image is only showing half of the page on my draft post and it is upside down. I am not into this technology and would rather use a spanner). I have attached a photo of the connector on my car which is different. There are yellow, brown and black coverings going into the connector. If anyone has a copy of the British workshop manual showing how to check for continuity I would appreciate a look at the relevant page. Thank you.

[BigBoomer]

Not likely that the horn switch is the problem.
Far more likely that the clock spring is the cause of the problem as they are a common point of failure for all the electrical stuff built into the steering wheel.

 

[steve2006]

Common problem read the link below regarding the earth connections.

Please make sure you disconnect the Battery and wait at least 10 minutes when disconnecting or reconnecting any yellow airbag plugs!

 

[Tomtit]

George and Steve.

Thank you for the replies. I wanted to check the horn switch because the workshop manual said to do that. I found a good earth at plenty of positions on the steering column.

I've had the car 4 years and there has never been a 10 amp fuse for the horn in the engine bay fusebox. The connection is there but the fuse is missing. The horn has still worked nevertheless, until now. The wiring diagram shows 2 horn circuits, one of which is for the security system and has a 7.5 amp fuse in the driver's footwell. This fuse is intact and there is power at the fuse connection.

I also found power at the 10 amp point in the fusebox. With nothing to lose, I put a 10 amp fuse in and the horn worked. Perhaps only one of the horns is working, but at least the car is road legal again. I might investigate further if the rain stops. If I discover anything interesting I will post it.

[Tomtit]

On 2/20/2024 at 9:44 AM, BigBoomer said:

Not likely that the horn switch is the problem.
Far more likely that the clock spring is the cause of the problem as they are a common point of failure for all the electrical stuff built into the steering wheel.

 

For the sake of £24 I took a chance and ordered an aftermarket clock spring. I fitted it today and had to improvise as the centre hole was too small to fit over the steering column. I got there in the end and the horn is working again. Thank you for the information.