RX400h Alarm Going off

[CornishDave]

HI

I have just got a 2007 RX400h , we went away on holiday early August and left it parked on the drive for 10 day  , when we cam back in all the heavy rain we found all the windows open and the alarm going off with the Battery almost flat ? i had a new Battery fitted and the local Toyota people have turned off the auto window settings but the alarm is still going off & i think its to do with water/rain ? we have also disconnected the interior sensor by the mirror & i have also remove the alarm siren ( drivers rear quarter ), but its still going off and sounding the car horns !! 

my wife thinks if she press the lock button on the key 3 times this stops it going off ?

has any one come across this problem , is there away in the setting to turn off the car horns ? Grrr ..... Alarms

[DanD]

Not an expert in these things, but I assume you have started the car OK?

Does the alarm still sound with the car in "ready" state and being driven?

Does the alarm still sound when the car is unlocked?

[PCM]

Is a drop in voltage setting it off?

 

[CornishDave]

Yea the alarm turns off fine by the remotes , but something is triggering it , but can't work out what ? Wondered if the car has a water leak and something electrical is getting wet maybe ?

[ChrisM]

Is there something alive in the car ? Insect perhaps.

My alarm went off the other morning because the suction mount from my camera fell of the windscreen and set mine off.

[PCM]

Have you tried the alarm when disarming the motion detection?

( the button near the front, inside light )

[CornishDave]

Yep the sensor is unplugged 

[The-Acre]

I've been pulling my hair out for weeks with a random alarm on my Volvo V70.  In the end I had to bite the bullet and take it to a main dealer who diagnosed a rear door lock as the problem. I've just fitted one at a cost of £250 (they wanted £420)  I know Lexus charge an arm and two legs but it may be worth getting a diagnostic, that should tell you which sensor is triggering it.