Topic

Any reason as to why my alarm would go off for no apparent reason? Could a low battery charge level be the reason?
The car is a 2002 with a two button fob.
It went off again while I was alongside looking around it, but not that close, so tends to rule out somebody tampering with it.

I know this may sound daft but mine was doing the exact same, found a fly buzzing around inside the car setting it off, as the inside has a sensor. you never know , just check and give the seats a whack and check under the dash both sides.

It's not gone off since, I took it out for a quick drive just to put some charge in the battery and have locked it with the key.

Tomorrow I'll carry out a test as described here
https://www.the-t-bar.com/forum/21-david-aiketgates-guides/11201-alarm-system-how-to-test

Hopefully I won't wake all the neighbours sometime in the night...

I have had this happen on my previous MGF -the MGTF uses the same driver door lock -so if you get no where with the tests and the alarm goes off randomly-then the problem will be in the driver door lock which has a microswitch to sense when the door is opened when the system is armed. The passenger door does not operate in the same way as the driver door. The door locks on the MGF are the same as the ones on the MGTF so easily obtained .Unfortunately the microswitches in the door lock are hidden away from the latching assembly so cannot be cleaned externally . The microswitch bank comes adrift internally and the this usually causes the random alarm problem . You could iether remove the door lock ( not too difficult-HOW TOOs are on this site) and replace it with a good one --or if you are electrically minded disassemble the door lock and repair the switch bank

Maddog1950 wrote: wrote:

Could a low battery charge level be the reason?

In a word, yes.

If the ECU detects low voltage it runs the fan to protect the engine, then as the battery completely dies it will sound the alarm. At this point there wont be enough power to do the central locking, let alone start the engine.

It had enough charge to start the engine fine. So it wasn't that low.

It's not gone off since, the tests all seemed to come back fine when I tested the alarm.

Do wonder if a spider perhaps set it off( there's some properly Impressive ones about at the moment) , movement of the wind deflector or even it was gently knocked by a neighbour (no sign of any scratches though).

Last time it went off for seemingly no reason I found out later, that on the next day there was a gang of thieves going around trying door handles at that exact time in another area of town. So I reckon they tried to get into my car that day. Really need CCTV...

Cctv is a great idea..sometimes it explains the unexplainable. .like recently one of my grandsons new football trainers had been taken from the car port....yes just the one...cctv revealed a fox in the early hours taking it and running down the road..the brightly coloured shoe clearly in it's grasp.