Alarm Issue-How to fault find?

[Poiret]

Hello all,

I have a 2007 XT4.  Mid morning today the alarm started going off for no apparent reason.  Turned it off, locked it again and two minutes or so later the alarm went off again so I turned it off and on again and yes it alarmed again, and again.....  I am guessing that parts the alarm system doesn't arm themselves for a short period after locking hence the delay?

I have found that by disabling the intruder/interior sensors it is fine so this suggests that it has something to do with them.  Yesterday I was dropping the back seats down and I noticed that the some water came out from around the lever in the wall that you pull to release the seats (drivers side) but thought nothing of it but the thought occurs that some water has probably got into one of the sensors.  I have had a look behind the removable panel below this lever and there is a small amount of water inside and while it is not much I am guessing that it probably doesn't take much.  I can see that inside this hatch there is a glass breakage sensor.  This must be connected to the alarm but I wouldn't have thought that it would be disabled when you disable the interior alarm.  Is there an interior motion sensor in there somewhere too?  Has anyone got any suggestions as to what I do next?  Could it be the glass breakage sensor and if it is why is that disabled when you disable the intruder alarm?  I would have thought that breaking the glass would be an exterior issue.

Also what is the ~3/4" white hose that I can see in that hatch and also on the other side.  It seems to come from the front and go out behind the bumper and they both seem to be empty and can't think what they could be for.

I know this is not the end of the world as I can still lock the doors but it does defeat the purpose of having a remote key if I have to get in a press a button every time I lock the doors so any thoughts would be gratefully received.

Cheers

 

[emin-j]

Hi, your model probably has a microwave sensor which is adjustable for sensitivity and will probably be behind the dashboard accessed through the glovebox,empty the glovebox squash both sides inwards and drop the glovebox down, the microwave should be visible to the right towards the radio, make sure there are no windows down a fraction also movement close to the windows can set off a over sensitive microwave (moving branches of trees etc) the white tubes you mention are probably the drain tubes from a sunroof.

[Poiret]

Cheers.  What I don't get is that if the sensor is oversensitive why has it suddenly started doing this.  It has been parked in the same place and there are no branches etc that could be setting it off.  The only thing that is odd is the water that I found was at the back but the microwave sensor is under the dash.  Also while it has calmed down now since I removed the panels at the back and dried it off it does still randomly go off at times but only during or after heavy rain.  What I would really like to know is how to fault find.  There's no sign of any water behind the panels now when it goes off so I suppose the water may have just been coincidence.  Also because it has now calmed down it's hard to know if tweaking the sensitivty has fixed the problem.  Is there any way of finding out exactly what it is that is setting the alarm off.  Does the ECU record such things?

[emin-j]

If set over sensitive microwaves can pass through the glass so any movement close to the car could set the alarm off such as a person walking past, the glass breaker picks up vibration such as the breaking of a window.I don’t think there would be anything recorded that a OBD scanner could read as the alarm has its own ecu and connects through the indicators and to the siren.

[IanML]

On ‎31‎/‎03‎/‎2018 at 8:08 AM, Poiret said:

Cheers.  What I don't get is that if the sensor is oversensitive why has it suddenly started doing this. 

Maybe water ingress to the sensor or alarm ECU has altered the conductivity or capacitance of a component?

[Poiret]

I'm beginning to lose the will to live with this now.  I am no longer convinced it is water but feel that that caused it.  Can anyone advise as to where the microwave sensor is.  I've tried behind the glove box but no luck although I'm not really sure what it looks like.  I  couldn't see anything with a knob to change a setting with.  I'm guessing it must just be a faulty internal sensor as when I disable it it works fine.  I was thinking of replacing it if adjusting the sensitivity doesn't work.  Is this easy to do?

Thanks for everyones help.