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Alarm challenge!


New Member
Sep 8, 2023
Country Flag
Hi there. So the alarm on my 2010 150 keeps going off... If I press the "theft sensor" button before locking then this does stop it happening.. My Toyota dealer think I need to replace wind screen (front and back) and all the sensors costing £1,800.. Is this feasible or are there some things I can try first..

Things I am considering. Batteries are quite old. The bonnet latch can be temperamental. However, if these were the issue would sensor switch stop it happening?
Leave the windows open for a day to let the moth/fly/bee/wasp/butterfly exit the vehicle
Think twice (or even three) times about entrusting your lc to a main stealer who 'think' you need to replace various items at the cost you state. If it doesn't work, they will 'think' of something else at great cost. They are mainly parts changers these days.

I am not familiar with the 150, but as Karl says, there may be a flying insect inside, or even a spider inside the sensor housing. On the 120 this is centre above interior mirror where the interior light/button is, maybe same on yours ?
You could try gently removing the housing to see if a spider has nested in there, or very gently applying air.
Batteries, hmm, even when mine were so knackered it wouldnt crank it woudnt affect that.
As you know your bonnet latch can be temperamental, I would make sure you get it sorted so that it latches properly and doesn't affect the bonnet sensor.
That sensor with button inside is for picking up movement, if you leave kids/dogs in the vehicle OR any other little beasties as Karl listed.
That sensor, as you may have found out, is cancelled every time you turn ignition on, so next time you have to push the button again.
Thanks both. This is what toyota think it is. What doesn't make sense is as far as I understand the deactivate button only stops the motion sensor not the window sensor. So why does pressing the button stop it going off if its the glass?

Maybe I should just change the motion sensor myself and see! Struggling to find anyone local who can be bothered to help!
Also I've greased the bonnet latch and is now working fine and agree unlikely low battery.
No great insight here, but those windows are not the front and rear screens, they are the quarter lights at the back of the car.

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I always thought it was the interior motion sensor that detected breaking glass tbh
Where/why would motion sensors be in/on glass anyway, when there is already a motion sensor system in place?
I've carefully looked all over my glass areas and can't see anything apart from the black spotted outer perimeter area on some ?
Whats the first £320 quid for on that quote? Does it make sense to anyone?
It looks as if it could be A "gen check and report", but not that clear, + vat though !
Or is it labour + vat as listed at the bottom breakdown £387.50 ? Hmm....
Leave the windows
This is the first thing I did when mine did that. I left all doors open and cleaned the truck.
Not sure about exact reason but it went off few times after I came back from Avalanche meet. I slept in the car there with windows open and some insects came inside while I was watching my phone.
I don’t have any issues now.