mx5cartalk.com

So I press the key fob to lock the car and then it does a double beep on the horn at random intervals long after I leave it.

At the moment it's in the car port beeping the horn every 3 to 10 mins - driving me nuts.

I've noticed this behavior once before but usually doesn't happen.

Things I've tried,

1. Disarm, then re-arm.
2. Disarm, turn on engine, shut off engine, re-arm.
3. Disarm, then leave it.

None of these stop it.

Last time it happened, I drove it home(20mins away) and it stopped happening.

Is there a clear incident function? I think the alarm is trying to tell me the car alarm has been triggered while I was away and needs acknowledgment?

I don't have the factory manual so can't check :S

Help?

Sounds like your 'NB8A factory alarm' might be what was referred to as the upgraded model sourced locally by dealers. If so, it probably has a backup battery for the siren, which sounds when the backup battery gets weak. In the short term you may find you can use a siren key to turn off the siren sounding. Siren keys look very similar to the key that used to come with computers years ago to lock/ unlock them: http://www.maplin.co.uk/images/300/2441i0.jpg
There may also be a alarm disable switch hidden away somewhere on the car.

I'd just get an auto electrician to remove the alarm altogether.

The NB has an immobiliser as standard from memory, and thieves tend to ignore alarms (or just cut the wires to the siren leaving it useless)

thanks for the input, there's no siren, the beeping is from the horn.

If you haven't already, for the short term, just disconnect the horn.

Hehe, that's exactly what I ended up doing. I've put the horn relay back the morning after and haven't had the alarm problem since.

Business in Bayswater- Mountain Hgy remotes cameras etc - on the corner easy to spot - top operator and highly recommended by many.

Contact guys - is Dynamic Car Alarms and Reverse cameras 9738 1616. This business gets good feedback and the Mgr is very helpful.

Yeah I know that shop. Generous guys, needed a key fob battery and the contacts had broken off. The guy soldered it back on but only charged for the battery.