Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Horn stuck on (and loud...)

Hello

The horn on my 2001 +8 is loud enough to be properly useful in modern traffic, which is great.

However, its currently stuck-on and at this point I'm not sure whether its the centre-of-steering-wheel switch, or the horn unit. I need to turn it off though!

I think I've located the horn just in front of the bulkhead but would really appreciate some advice on how to disconnect it?


many thanks

Tim
The convention is that the horn is earthed through the steering wheel boss, so take that off - it should just pull out of it's Motolita, but may need persuasion. Inside you'll see a simple spade connector. Disconnect that. If the horn is now off, the fault is in the boss. If it still sounds then you have a short to earth between the horn and steering wheel. The horn should have two terminals - 12v in and 'to earth' out. Convention is that the earth out lead will be purple with a black tracer but this may vary. You can test which is 12v supply with a test bulb. There will also be a fuse for the horn, so if you can identify it, pull it out if required.

If both the horn and the steering wheel button were to go to earth, there would have to be two circuits, the second actuated by a relay in the first.
However, looking at the wiring diagram on GoMog, it would seem that the horn is not earthed, and the circuit is: fuse to horn to steering wheel switch to earth.
So the horn is always live when the ignition is on, and as DaveW suggests, the fault is most likely to be somewhere between the horn and the steering wheel button. I would suspect the switch itself or the wiring between it and the stationary part of the steering column - is there a slip ring? or is the wire just wrapped around the column, winding and unwinding as you turn? Alternatively, there is a fault in the horn earthing itself (unlikely, I would think).

Fjemog

thanks both - pulled out, with fingers, the horn switch unit from the steering wheel. The earth spade connector had managed to embed itself into the 12V 'in' wire, cutting through the insulator, hence the short circuit. All fixed now. Many thanks again for the advice.

Hi Tim,

I hope you received the Wiring Diagrams I sent you by email. I lifted these from GoMog and have been really useful in fault finding.