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Horn honking randomly!
Posted: Mon Jun 14, 2010 3:13 pm
by christhemann
A wierd annoying problem...hope someone's had similar?
Got in the rocco the other day to start it, and the horn started honking randomly.
First thing I tried was to take the steering wheel centre out, and check the wires. As I did this, somehow one of the
spade connectors snapped off!
Got that problem sorted as I have a new steering wheel middle on order (courtesy of someone on here!)
But the problem still remains, even with the horn wires in the steering wheel taped up it still honks!
I've had problems with horns before on other cars,but usually them NOT working due to poor connections.
Someone mentioned the earth wire to the steering rack, etc.
Any ideas ?

Re: Horn honking randomly!
Posted: Mon Jun 14, 2010 7:31 pm
by christhemann
Update:
Now i'm pretty confused...
-Had a thought it could be the No.53 (Horn) relay, so took this out. Horn still sounding.
-Took fuse 18 out, still sounds!
-Physically disconnected the horn cable in the bonnet-Now the engine won't start! Just a click.
I had a good look at the fuse box, and theres no leaks so doesn't look corroded at all.
Cars got a Cobra alarm and Clifford immobiliser. Neither are connected to the horn in any way I don't believe.
(alarm has its own siren).
Nothing's changed recently, just decided to start playing up!

Re: Horn honking randomly!
Posted: Mon Jun 14, 2010 7:42 pm
by ianaudia4
Has someone connected the live feed straight to the horn, maybe tapped into the live to the starter motor?
Re: Horn honking randomly!
Posted: Mon Jun 14, 2010 8:28 pm
by christhemann
Hmm, no it doesn't look like it.
Why would anyone do that?
Starter connections are all good.
The car was working just fine a few days ago.
Any chance it could be the ignition switch? Seems odd thing to be setting the horn off though...
Re: Horn honking randomly!
Posted: Mon Jun 14, 2010 8:43 pm
by ianaudia4
Something to do with the immobiliser via the ignition? What about the earth?
Re: Horn honking randomly!
Posted: Tue Jun 15, 2010 9:20 am
by christhemann
Just looked at the wiring diagrams for the alarm and the immobiliser.
Neither of which are even connected to the horn.
Bloody electrics
Re: Horn honking randomly!
Posted: Tue Jun 15, 2010 1:01 pm
by the edmundator
When weird stuff like this happens, it's usually a bad earth, a poor connection, corrosion, knackered/damaged wires, or a faulty switch. Take your pick.
Re: Horn honking randomly!
Posted: Fri Jun 18, 2010 10:48 am
by christhemann
The game continues!
I replaced the 53 and 18 relays with new ones, no change.
Have checked the immobiliser which seems to be fine, the alarm is still working in the sense that it unlocks the doors remotely.
Have dropped the fuse box down and inspected it, replaced all fuses and it all looks fine. Can't see any corrosion and theres no water leaks in the car now.
Have been looking at a wiring diagram for the Cobra alarm, and noticed that the ignition on (+15) feed goes to the black/brown wire on the horn circuit at the back of the fuse box!
This is odd, as the alarm has its own siren and never activates the horn normally. It can only use one siren.
Spoke to the original alarm fitters, who are none the wiser.
It also has a seperate immobiliser that was fitted prior to the alarm, but has no connection to the horn that I am aware of, it uses a little fob that needs to be near the steering wheel.
Any help much appreciated!
Re: Horn honking randomly!
Posted: Sat Jun 19, 2010 3:35 am
by Whitescala89
Maybe gremlins do exist!

Cant think though
Re: Horn honking randomly!
Posted: Mon Jun 21, 2010 3:20 pm
by christhemann
Think I might have found the gremlin, just need to squash him now!
Took the whole fuse box out, and low and behold behind was some corrosion, and below.
This makes sense as the windscreen had a leak some time ago (fixed now), but may have caused lasting damage.
Anybody know if its possible to disassemble the fuse box and clean it up? Seems to be glued together.
I've sourced a replacement, but also like to make sure its nice and clean inside.
How about soaking the whole thing with WD40??
Cheers.
Re: Horn honking randomly!
Posted: Mon Jun 21, 2010 8:12 pm
by Funky Diver
I wouldn't be soaking anything electrical with WD matey, unless you fancy a small fire on your hands under the passenger side of your dash.
Re: Horn honking randomly!
Posted: Mon Jun 21, 2010 9:34 pm
by christhemann
Thanks, will give it a miss then.
Some people mention using contact cleaner spray, which works better than WD40 as it leaves no residue...