Horn started sounding continously at 1am

Hi,

I would appreciate some advice on troubleshooting a weird problem on my 53 plate Td5 auto. At one oclock in the morning, the horn started sounding continously. The car had been parked for several hours at the time. A quick dash outside in my dressing gown, and I pulled the horn fuse. But why would it go off on it's own like this.

Suspects are horn switches - my wife has had problems knocking these, and it did seem in the morning that one of them was sticking slightly in it's hole.

Horn relay - could that decide to complete the circuit on it's own?

Rotary coupler? Hope not at £100+!!!

A short on either side of the relay?

When I bought the car, one of the horns was faulty, and the fuse was blown. I've put a new horn and fuse in. So maybe there was a problem before... But I keep coming back to why would it go off hours after being left standing.

Any advice gratefully received.

Cheers!

try this...
http://www.landyzone.co.uk/lz/f8/alarm-goin-off-4am-99646.html

does your alarm go off on the horn or siren?
either way, it points to possibly some form of damp somewhere or BCU related...

My D2 2001 did exactly the same thing the other night, suddenly at about 9pm the horn started and continued, I went out to it thinking it was the alarm, tried the key fob to unlock it still the horn continued, put key in ignition and it started so new it wasnt the alarm / immobiliser, on starting it noticed one of the 2 horn buttons to be slightly depressed / stuck, popped it out and the horn stopped.
Turned out the other half had used the horn that day, obviously unknown to us the button had stopped in slightly, assume that a change in tempriture within the car had then been enough to cause the button contacts to make when things had expanded in the heat.
Maybe yours was something silly like that too.

mark-w said:

Maybe yours was something silly like that too.

Click to expand...

Hi Mark,

I have to say this sounds very similar, and I definitely do seem to have sticky horn buttons! I took off the sterring wheel to fit cruise control, so maybe something moved when I did that. I will take them off again and refit. New ones cost about £50!

Thanks for your input.
Cheers!