Alarm connections

Good afternoon all,
For the sake of preserving good community relations please help me! Our 1998 TD5 has been waking up the neighbours. The alarm has started going off unprovoked. The old bus has suffered a little from the damp recently and I suspect that is part of the problem. I've had to disconnect the alarm sounder and take the horns fuse out to get a night's rest, but would like to have the horn working again. There must be a connection from the alarm to the horn relay (that I could disconnect). Has anyone done this or know where to find it? Thanks for any advice ...

There's no direct connection between the horn relay and the alarm why should there be.
Your alarm system is voltage sensing therefore the horn sounding will activate the alarm when set.
Has the alarm has stopped activating now u have removed the horn fuse? if so your problem is with the horn circuit.

I haven't seen the lights flashing, (but it was intermittent anyway) so I don't know if the alarm has been triggered. I only need the horn when the alarm isn't set obviously (ie when driving) .

Now I think about it a switch to connect/disconnect the horn would do it.
Please explain further 'voltage sensing' ?
Thanks for you help

my advice is to not go for such bodge to put a switch on the horns circuit, you better investigate and fix things cos if it's caused by water ingress you might end up with the car immobilised and then if you dont know the EKA you are f***ed, also if the alarm goes off without sound it will make it's programm anyway which is not healthy at all.

take the risk, leave the horns connected and close the door with the key(not with remote) and if it will stay silent it means it was triggered by the volumetric alarm, if the alarm goes off even when the car was locked with the key there could be many reasons, non of them to be neglected.

the BCU records why the alarm was active last 3 times so the simplest thing would be to plug in a dedicated tester... being there you can set the alarm to silent too if you want

The last 3 times were me setting it off by waving at the volumetric sensor through an open window! What do you mean 'also if the alarm goes off without sound it will make it's programm anyway which is not healthy at all.' ?
Is it possible to disconnect the sensor rather than just use the key?

If you've had water in through the sunroofs, there's a strong possibility that the volumetric sensors will have corrosion on the back of the PCB, causing random alarms.

Mine did this but I only had the lights as the LPG vapouriser ended up where the sounder is.






Note that D2's have a separate sounder for the alarm, it is not the regular horns that go off when the alarm activates.

The other possible is salt getting into the bonnet switch, right-hand side by the ACE/Power steering reservoirs.

Peter

Thanks, yes I found out that there was a sounder too but the horns go off as well. Did you disconnect the volumetric sensor or replace it?

i meant that if you diconnect the horns and the alarm goes of several times in the night)while everybody is sleeping as it's silence) it might drain your battery down and if the battery looses power while the car is locked and it's not set on "always disarm with key" it will be immobilised immediately when you unlock with the key cos the battery being dead the remote doesnt work...then you need the EKA(dont ask me what's that pls, search)...cos if you dont know what's that you might be in deep sh*t in the future m8

you can disconnect the volumetric sensors or find somebody with tester to disable the volumetric alarm if you are sure that's the culprit

the alarm can be set to sound many ways: horns + alarm sounder (+ BBS if fitted), only horns, only sounder, only BBS, not at all

plumbfisher said:

Thanks, yes I found out that there was a sounder too but the horns go off as well. Did you disconnect the volumetric sensor or replace it?

Click to expand...

Replaced it, £10 on ebay.

Can't remember if there is a BCU step to include the main horns or not, unless someone had played around and brought the main horns in as well.

Peter

There are a variety of possibles:



Peter

Thanks for all replies.
I've had a look at the sensor and there was a little corrosion around the base of the socket, but no visible damp. Cleaned it up with a toothbrush.
The bonnet switch is very clean and dry.
I'll lock it up again and hope for silence and an undisturbed night ...
Thanks again.
By the way Peter, great website - I shall be gleaning info from there for sure!

I have a 2003 Discovery when the alarm is activated, the alarm sounder rear nearside of engine bay and main horns by radiator all sound at once. The car is standard so I think this is normal.

i had an issue once, whereby i thought the alarm was going off in the early hours of the morning. in fact it was the horn buttons on the steering wheel playing up. they would partially stick down and go off randomly. generally 3 in the morning.