Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Ignition/horn fault?

Hi all

Had a problem today where I turned on the ignition and the horn sounded continuously turned it off and the horn stopped this happened three times. Eventually the engine started up and the horn went silent. It seems ok now but I'm in Belgium (Spa classic) and I was a bit worried.
Has this happened to anyone else on here?

When the ignition is turned on but the engine not yet started, a current flows through the ignition circuit including the ignition light to the alternator to excite the field coils. You then start the car and as soon as the output voltage of the alternator is greater than that of the battery this current stops and the ignition light goes out.

For your horn to sound when the ignition is turned on and then stop after the engine starts means that it is picking up voltage from this initial starter system. It should not be doing that and somewhere in your wiring you have a short.

The very fact that it doesnt sound when the ignition is off suggests that its unlikely to be a problem when the car is parked up. But you do need the services of an auto electrician and likely he will need to go behind the dash.

Thank you Howard
I thought it would be a short somewhere luckily its 5 months old so it's a warranty job. It did rain heavily at times down to Spa so probably played a part, stayed dry on the inside though so Silver lining

It may seem dry inside but water often gets behind the dash due to leaks via the bonnet hinge screws or wiper arms.

Did the starter turn initially?

If not you may have a poor earth connection between the engine and chassis return/ground.

Maybe but that still should not activate the horn unless the horn button is stuck depressed too ie the ignition circuit is being connected to earth via the horn which is switched on. Somehow the horn is in circuit when it should not be

I suspect a relay may be getting an incorrect signal. Why is another matter.

It's weird drove all the way back from Spa stopped a few times on the way had no problems at all. I'll still take it in just for peace of mind.
But the Spa classic really great time, pictures to be sorted.

It had been raining / the car had been washed when you had the problem ie water in somewhere? More likely a loose wire?

Having said all that, is your Mogan really modern and have MMC gone over the that work of the devil - CANBUS? If so its beyond me. I'm strictly a points and carburettor man.

CANBUS on Aeros only Howard, so not on a +4. Totally agree about work of the devil, fiendishly difficult to fault find since totally odd things happen intermittently.