Hi all, just back from a trip to the big Island and had an interesting experience when using one particular multi-story car park in Southampton.

Each time I parked the alarm went off unless I disabled the interior movement sensors with the door button. I have the panoramic glass roof and I noticed I was parking under a fluorescent light. After the first time I actually stood by the car until the alarm went off so I know there was no normal reason for it.

So is it possible that there is a light sensor inside the car as well? If so sunshine doesn't set it off. Maybe it was something to do with the frequency of the light.

I had no problem in any other car park that we used so I would be interested if anyone knows of any reason for it.

Thought the sensor were just volumetric. Was it West Quay? You get a lot of structural vibration in parts of it where cars pass over certain points.

Thought the sensor were just volumetric. Was it West Quay? You get a lot of structural vibration in parts of it where cars pass over certain points.

West Quay was no problem, and we also used multi-story's in Salisbury, Christchurch and Boscombe. It was only the Marland where it went off, first time was early in the morning when there was very little vehicle movement. I locked the car several times on 2 separate days as I was ferrying shopping back and each time I stood by the car so I would have seen anything that may have set it off. It must have happened 3 or 4 times. After that, I just pressed the door button without waiting to see if it went off again.

Mine has the glass roof and I have tried very hard to reproduce your experience. I have even alarmed the car in the darkness of my garage, then switched on the overhead fluorescent lighting. Nothing!

Next time the alarm goes off, try closing the roof blinds to see if it makes any difference.

Thanks for that. We won't be over now until the same time next year but I'll try it then. I did close the biinds but also pressed the door button..

Hi Calomax,

Did you ever find the cause of the problem?

Mine has given a couple of false alarms during two years of ownership, but never in multi-storey car parks.

Rob

I had a glass roof Roomster for 3 years. About 4 or 5 false alarms. All unknown reasons.

A scan of the car with VCDS or similar will often give the last 4 or so alarm sources.

Hi Calomax,

Did you ever find the cause of the problem?

Mine has given a couple of false alarms during two years of ownership, but never in multi-storey car parks.

Rob

Hi Rob, I had completely forgotten about it. It didn't happen when we were over last July or October so it's still a complete mystery.

Hi Rob, I had completely forgotten about it. It didn't happen when we were over last July or October so it's still a complete mystery.

Never had problems with the alarm, until now. I have no glass roof.

I suspect it is all up to vibrations + torsion:

1) Maybe the multi-story car park you write about is subject to bigger vibrations

2) Maybe the glass roof structure is more subject to structural torsions, which are not harmful to the car, but added to vibrations, well, do something to the alarm system.

Maybe (I am no engineer)

Edited 20 June, 201115 yr by Lorenzo

could it be to do with the glass roof better reflecting the utrasonic waves and so any vibration in the glass affects the inerior sensors more? (which is why closing the blind could affect / stop it?)

and could it also be that particular spot in that carpark causes a vibration at or near the resonant frequency of the glass roof?

just my 2p worth, probably load of old tosh as well, but would seem to be the only logical thing i can think of

My Roomster3 hasn't had an alarm problem in four years. That includes, on occasion, isolating the interior sensors ("dog switch"). Sensible money on your problem is a fault.

John

My Roomster3 hasn't had an alarm problem in four years. That includes, on occasion, isolating the interior sensors ("dog switch"). Sensible money on your problem is a fault.

John

Maybe, but it hasn't happened again in 2 years including another trip to the UK last October and visiting the same multistory in Southampton. So I'm not doing anything about it. In fact I had even forgotten about it and that I had posted about it so long ago.

My Roomster Scout (with solid tin roof) alarm went off yesterday - no apparent reason so I switched it off for now - got into the car today and there was a fly buzzing around inside the front windscreen - could that set it off? Its never gone off before as far as I know. Yesterday was a hot day and it was parked in the sun, but that shouldn't set the alarm off should it? All doors and windows shut etc.

My Roomster Scout (with solid tin roof) alarm went off yesterday - no apparent reason so I switched it off for now - got into the car today and there was a fly buzzing around inside the front windscreen - could that set it off? Its never gone off before as far as I know. Yesterday was a hot day and it was parked in the sun, but that shouldn't set the alarm off should it? All doors and windows shut etc.

Ours has gone off 2 or 3 times for no apparent reason. Maybe a fly could do it.

Hi, my Roomster (model 2011) alarm went off 5 or 6 times last 6 months. The first 2 or 3 times the alarm doesn't stop either with the ignition on. The dealer has not found the problem.

Now occasionally the alarm light flash but without sound.