Car Alarm Going off for No Reason!

Mercury1

I got a Ford Mondeo (03) My alarm is repeatedly going off for no reason, most recently 1.15am this morning

Does anyone know what could be wrong with it? (Car Novice)

Many Thanks

Pew_Pew_Pew_Lasers!

Don't wish to frighten you but thieves have been known to repeatedly set an alarm off in the hope the owner would disable it for a good night's sleep, at which point the thieves steal whatever they can from it.

Chances are though its just a simple fault. An auto electrician should be able to diagnose it.

angelcake

My focus used to do this all the time! (I sat and watched it go off by itself!!)

I think it was a fault as there is with the standard for alarm!!

uktyler

What was the weather like?

My alarm used to go off when the weather was bad, especially in heavy winds, but then next doors cat could set it off by jumping on the bonnet! (not many times though, the poor thing scared itself stupid everytime he did it!)

vikingaero

Minimise the risk of it going off first.

(1) Open and close the doors/boot/bonnet to make sure one isn't partly open.

(2) If there's a plunger switch for the bonnet then push that up and down a few times to maybe get rid of a dodgy connection.

(3) Press the recirculating air switch/lever with the engine on and make sure you hear it whirr into position.

(4) Close all face vents

(5) Turn the air direction switch to the feet/floor

Then try your alarm. It could be something simple like the sensitivity needing to be turned down or a faulty sensor.

wilkies5

just a thought, to add to other suggestions. We had a problem with our vauxhall zafira a while back. Its alarm kept going off and we found that the sensors at the rear of the vehicle (above the rear screen) were faulty, and were sending alarm messages to the pick up points at the front!

get the vehicle checked - is my advice, else it will send you crazy every time it goes off!

good luck

Jorgan_2

It may be a faulty alarm sensor in the car, shouldn't cost a fortune to fix if it is. Does your car have a way of turning off the internal alarm sensors, if so, turn them off & see if the problem persists.

jeannieblue

Have had experience of Avensis' alarms going mental - one lady said her car kept 'singing':D Dealership said that they needed to replace alarm system (1k plus), we took a look, the siren looked a bit ' manky' (technical term) - replaced it - part was around twenty pounds, its been fine since and this has happened to a number of them since then.

Love it when the solution is simple - and cheap.

hewhoisnotintheknow

my money is the ultrasonic sensors (the things that pick movement up in the car) most cars ive had with alarms have had issues with these, easy to replace, there will be a button in the car to turn these off, try it and see

Swanny

My Ford Focus had a similar problem, it turned out the bonnet release was faulty and the alarm thought somebody was trying to break in so it went off quite randomly. Less than £100 to fix two years ago.

RaCinG_SnAkE_3

What condition is your battery in? If it's not able to hold its charge too well, this may be the cause.

Most alarm systems have a threshold voltage that if the battery dips below will start the alarm going off. This is due to the alarm system "thinking" that someone has disabled the battery.

Another possible cause, which happened to me, was that the bonnet release sensor had filled up with water causing corrosion in a switch, effectively completing the circuit and setting the alarm off.