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Discussion Starter #1
...at about 04:00 today. With the car locked.

And it wouldn't stop... :(


The car had been driven on Wednesday afternoon, then left locked. On Thursday night, as I was going to bed, I heard what sounded like a single little peep from a car horn outside, but looking outside there was no sign of life from any of the nearby cars.

At 04:00 I was woken by a car horn sounding continuously. Not an alarm, just the horn, one continuous note.

Suitably attired in a dressing gown I went outside. The Mito horn was sounding, but no lights flashing. I went back in and got the keys, unlocked the car, locked it, nothing made any difference. I wanted to disconnect the battery, but being half-asleep I couldn't remember which side the bonnet handle was. I bumped against the steering wheel and the noise stopped briefly and started again. I tried pushing the horn pad but that had no effect. Then moving the steering wheel very slightly caused it to go off again, eventually jiggling the wheel allowed me to find a position where the horn stopped.

Then I popped the bonnet and disconnected the battery.

I don't know what the alarm sounds like but this seemed to me to be just the horn. I guess if it does it again it will just run until the battery is flat, so I can't leave it unattended with the battery conected.

I'm setting off on a trip at 07:00 so I'll have to leave it disconnected for now.

Aaaaargh !
 

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Sounds like the steering wheel contact for the horn is just too close to the opposite contact and the horn is going off but what a pain to have that going off :mad:
 

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Discussion Starter #4
I don't have time to investigate now, but yes, pulling the fuse should give some peace of mind until the dealer can look at it. I can't afford for it to do this while I'm away - the neighbours would go ballistic...

The fact that nudging the steering wheel made is stop/start the noise suggests to me that this is due to whatever connection exists between the wheel and the rest of the car. Or maybe touching the wheel discharged some electrical potential that was causing noise in the system, I don't know whether the horn is a dumb connection or some sort of signal on the electronic bus.

Anyway, I'm off for today and the Mito can sit on the drive with the battery disconnected, I locked it with the bonnet open and then pulled the battery connector and closed the lid.

More later when I get a chance...
 

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Discussion Starter #9
ok, I've just got back from a 300-mile round trip in the other car, and the first thing I did was to open the bonnet on the Mito and reconnect the battery. Even before I had a cup of tea - that's how annoying it is.

Instantly the horn sounds continuously.

I didn't try the wiggling the steering wheel thing, it was simply making too much noise - the dealer can do the research on their own premises !

I've pulled fuse F10 in the box next to the battery and all is quiet, the car appears to be functional apart from an 'Alarm unavailable' banner on the display. I suppose using a meter in the fuse position would allow some measurements without going deaf, that's for them to work out.

I'll be ringing the dealer shortly.
 

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changin the subject a tad,,,did u get ur keyring hun???
Yes I did thanks Tess, bought it from Classic Alfa, cost around £12 with P&P in the end. Little more than what you paid, but had all the colours to choose from, choose the red! Looks cool, just need me car to go with it now! :thumbs:
 

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Discussion Starter #13 (Edited)
*Update*

The dealer had the car for a couple of days. They couldn't reproduce the problem but they did tape a couple of wires into a different position. They talked to Alfa about the clock spring, but that wasn't actually changed.

Last night it did it again..... :(

Luckily we were in. The car had been used early in the morning, then locked for the rest of the day. At about 9 in the evening it simply sounded the horn as a continuous note. This time I was ready - I unlocked the car and moved the steering wheel slightly. Moving it would interrupt the noise, but only briefly, and I couldn't find a steering wheel position where the sound stayed off completely.

Then I pulled the fuse.

Won't be able to talk to the dealer until Monday, but I think that pretty much confirms that it is in the steering wheel/car connections, so we'll insist on all the relevant parts in that area being swapped. We really can't stand the thought of it doing it while we aren't there - we'd been out all day on Saturday and if it had started earlier it could have been sounding for hours




*** Further update ***
I couldn't resist doing some diagnosis.

I started with the car just as it was left when I pulled the fuse last night. I was measuring the voltage at the horn fuse socket.

Engine off
Multimeter shows 9.5 V, wiggling the steering wheel can occasionally get that to drop to zero but given that the engine is not running there is limited movement of the wheel. I couldn't get it to stay at zero. The meter actually showed some intermittent readings of over 20V (it was on the 20V range and blanked to the overvoltage indicator a few times as I moved or bumped the wheel)

Pressing the horn pad gave a stable reading of 12.3V

Engine running
I gave the wheel a couple of twirls with the car stationary, then more measurements.
Reading is zero EXCEPT on full left lock, where the reading is a stable 10.0V while the wheel is held gently against the limit. This reading occurs only when the wheel travel is actually stopped at full lock, backing off from full lock it drops back to zero. Twirling the wheel shows some indication of non-zero readings but they are momentary.

Pressing the horn pad gives a stable reading of 14.0V

Enough evidence for something, but what ?
 

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Discussion Starter #14
Final update (I hope...)

The dealer took the car away for a week. They were unable to reproduce the problem or any of the readings I showed in the previous post.

They have changed the clock spring assembly.

The car was returned yesterday and so far has behaved itself...
 
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