My car is fitted with the original H&P alarm system, and has never given any problems from new, but, after a clean of the engine compartment at the weekend, the alarm keeps on going off! Strangely it is mainly overnight, which is a real pain.

Having done an extensive search I can't find a thread which really helps. I can confirm that there has been no rain overnight, that the battery is new and that the bonnet sensor is working correctly!

Has anyone had a similar problem, and, if so, how did they cure it? In the meantime, is it possible to deactivate the siren itself, without affecting the rest of the alarm system (i.e. immobilizor and door locks)?

TIA

 

Check you haven't got any flying insects int the car that come out at night. I had this with my old car and it turned out to be a moth triggering the sensor but only happened once it got dark.

 

Try locking it with the key, the immobiliser will come on after 30 seconds anyway, but the alarm itself won't be armed (I think).

 

Has it been very windy Dennis?

 

Nope!

I suspect water has penetrated somewhere during the cleaning process.

cupracing: Nothing trapped in car, and it has also gone off during the day.

lovegroova: I will try that, but I suspect that the siren will also be set. I will report back later!

 

Not sure of the diagnosis (strong winds/any friendly neighbourhood cats...?!).

In the meantime though you could try disabling the hyper-sensitive element of the alarm, i.e. press the lock button, wait three seconds, press the lock button again (indicator lights should flash three times to confirm it has been disabled).

 

I don't think doing that, to deactivate the interior sensors, would work with the hood up? I will try it, but I don't think it will do anything.

(Note: A mod carried out to the alarm system late 2002 means that these sensors are deactivated automatically when the hood is down. Some owners do not realise that this happens!)

 

Dennis,

I've just remembered, using the key definitely does mean the alarm is not enabled, only the immobiliser. It will work in the short term.

It might be worth running the engine for a while with the bonnet open in order to get some heat and dry air into the alarm components and dry them out properly.

 

The alarm went off at about 10-30am, so I have locked it with the key and I am waiting to see what happens!

The car has been used several times since the false alarms started, and I thought that the under bonnet heat might resolve the problem, but it has not done so.

Thanks for all the replies!

 

Hi Simon,

As I said earlier, I locked the car on the key at 10-30am and it's just 9-00pm and Snoopy has been as quiet as a mouse.

You have given me temporary relief until I can find out what the problem is, or it cures itself, so it looks as though the wife & I can sleep through the night without interruption.

Thanks.