My alarm kept going off for an hour during one of those extra-heavy downpours the other day. The Ultrasonics were disabled each time to prevent noise triggering it, but that didn't stop it. I did wonder whether moisture got into a sensor, but no signs of any leaking. Its been O.K. since the rain stopped. Anyone suggest any cause -I'm just curious?

Thanks,
Trev

 

I appreciate it's not always possible to predict when the rain is going to be heavy or the wind strong, but if you are aware of a bad forecast, it's probably best to turn off the internal sensors.

The procedure varies according to model year, but IIRC, you press lock again within a couple of seconds of first arming the car.

I think the roof moves in bad weather and this triggers the interior sensors ...

 

Bonnet sensor is the usual culprit for triggering in very wet conditions...

When you disarm, the number of flashes will tell you what's triggered.

 

I agree roof movement or even an insect trapped inside the car can trigger the sensors. On this day the internal sensors were off and no unwanted occupants, and had to be turned off again each time it triggered - thats why it's a mystery to me.

Trev.

 

It happened again last night in heavy rain, but this time I remembered the tamper indication. It says bonnet opened - so its either water causing the sensor to trigger or vibration of the bonnet. Anyone know where this sensor is, please?

Thanks,
Trev.

 

I get the same problem but fitted my alarm on MY99 i think on a stock alarm its about 8'' left of the bonet catch but have seen them half way up the drivers side 'wing' thats where mine is and thinking about moving it!
They should make them with rubber gators, its really anoying i know.