Resetting / disabling a car alarm

[AstralTraveller]

Technology has me stumped.

My mother has a second-hand Mazda 121 and, since she doesn't drive much any more, the battery went flat. So I removed it, charged it and had it tested - it's OK. However when I put it back in the car alarm went berzerk - and keeps going berzerk until I disconnect the battery. Before this I hadn't even noticed there was an alarm! We have never used it and before this it's never made itself obvious. What I have found is a big horn speaker (which, yes, I should have noticed earlier), a switch to detect when the bonnet is up and a little red LED on the dash. I can see that extra wiring has been added to the loom but I has been done very neatly and the who lot wrapped in tape so it's impossible to see the extra wires. Some certainly goes through the firewall under the dash but I couldn't see where it goes, except to the light. I couldn't locate the control unit and don't know what it should look like. I've looked through the cabin for anything like a switch but found nothing.

So I'm stumped. Does anyone have any sort of clue what I should do next. Petrol and a match does seem a bit drastic :).

[Baddad]

Look for the switches and see if they are the culprits.
If switches are left idle for a long time insulating corrosion builds up on the contacts.

Other than that I can't help much without being there to check it out.
A trick I used in the army was to drive a pin through the wires on the back of the switch to see if it made a difference. ie. do the job of the contacts

It depends whether it is a make or break contact to trigger the alarm.

That is my initial thought. There must be door switches boot etc they all need checking.

The main control box may be hidden behind a panel in the boot or behind a side kickboard. passenger or driver side.

Good luck. Without seeing it myself I can only give you limited help.

Cheers:)

[Kunama]

David the siren and alarm control are often in the same enclosure, there should be a key switch at the back of it. Hopefully you received a small key along with the car keys. That will disable it. It may also have been made with a wireless remote.
Can you see a brand name on the siren?

[LewisM]

Try the alarm on a VW Passat... Had a fault in the computer once, and the alarm started sounding (not so bad outside the car, but inside, it is nauseating!). So, I disconnected the battery.

Alarm still going...

WT????

Take battery out (which is NO easy feat in a VW Passat considering it is buried UNDER the coaming behind the firewall, and needs Houdini to wangle it out.

Alarm still going...

Put battery back in, try the alarm disable again (button hidden on driver side door post). This time it stops.

Take it to VW mechanic, TRAINED by VW/Audi (and he is German). 3 hours after I drop it off, I get a phone call. I could hear my alarm going off in the background. Achim yells "How the himmel do you turn off ze alarm???!!!". I said you are the VW expert, YOU tell me!!!!

They had to reflash the computer :)

Every now and then it acts up. I think water gets into the computer compartment (under the driver's floor) and plays games.

BUT, can't complainm = over 300000KM, and SO few problems. It throws bearings every 2 years, but I am cheap and put aftermarket in instead of FAC bearings :)

[pw]

I had an aftermarket immobiliser & to change its settings you turned the ignition on & off 5 times quickly. You could try something like that with your crazy alam.

[noeyedeer]

lift it above a towing angle like arnie does in some movie ... that's all I know lol .. or just find the alarm and cut it's wires. take it to an auto electrician and get them to remove the problem or fix it etc.
matt

[Lee]

Wire cutters vs horn speaker??? Who would pinch a 121 anyway?? :P

[john guy]

if its possible to know who the selling dealer was they may be able to let you know the type of alarm fitted, this may be genuine mazda alarm or repeller. just try when you reconnect the battery to have ignition key tuned on before you connect the battery terminals

[AstralTraveller]

Thanks for the advice everyone. Peter had the correct approach, though Lee's was perhaps more satisfying, but I must take issue with him on one point. IMHO a 121 is a very desirable vehicle. It is:


cheap to buy
cheap to run
offers easy access for the aged
cheap
easy to park
keeps the driver (and passengers) in intimate contact with the road - every bump and pothole
inexpensive
the power won't scare the horses (or the grannies)
more luggage space than it appears
cheap, cheap and cheap

[Lee]

All true.... but still - who would pinch one??