Alarm Going Off - Fault?

[MajorClanger]

My 98 Chimaera has been annoying the neighbours for the past two days with the alarm siren going off. I've checked all the doors, boot, bonnet switches and they're all working fine and all are properly closed. The alarm does not flash in code to tell me which of the sensors is setting off the alarm (but not sure if the flashes come after you have just unlocked the car or whilst locked). Funny thing is that the alarm only goes off when no one is there and only during early afternoon.

Any ideas what could be wrong? Could it be caused by the air inside the car heating up?

Is there any way to disarm the alrm whilst locking the car? What does the fuse for the alarm do (won't this just set of the alarm)?

Any help greatly appreciated.

MC

[Jarrett]

You could eliminate the hot air theory by arming the alarm without the internal sensors on. If your alarm is the same as the one in my old Chimp then you do this by holding down the button on the key fob for 4 seconds not the usual 2 (careful though as I think that 8 seconds is the panic alarm!). If it works the indicators will flash differently, 3 times not two or vica-versa.

Obviously only do this somewhere where you are happy to have the microwave sensors off. If the alarm stops sounding then it may be this.

My Griff alarm started doing this after I had had the car for about 2 years. The alarm would go off for no reason initially then after a few weeks it started going off when I unlocked the car!! Eventually had to rip the siren off and wait for the backup battery to run out before taking the car back to the dealer (took hours!). Turned out to be a faulty siren that was shorting the alarm.

Hope this helps and good luck cause I know how bloody annoying and embaressing this can be!

[thb]

You might want to try turning down the microwave sensitivity - its quite an easy job, if a bit fiddly.

Basically, you need to remove the pad at the bottom of the loose change holder at the end of the transmission tunnel. You should then see 2 screws. Once you have undone these, you can lift up the whole of the trim over the transmission tunnel (theres not really any need to undoe it at the front - you just need to tilt up a bit). Under this should be a little box which is the sensor. On the box, there should be a little screw hole - adjusting the screw adjusts the sensitivity (from memory, if you tighten it up clockwise, the alarm should become less sensitive). Then its just a case of winding down a window (waiting for a few minutes for it the alarm to set properly) and then reaching into the car to get the right level of sensitivity.

Of course, I have heard the sensor is behind the dashboard on some cars...

[ChrisCh]

Whatever you do be careful.
A friend of mine had a similar situation at 4am each morning, he turned his alarm of one night because he was fed up of it going off. Woke up next morning and his pride & joy had gone, obviously someone had been setting it off as a test.
This does not solve your problem but be warned!

[RCA]

One way, the way a lot of people get locked out is too lock the doors from the inside, they will not unlock until both doors have been opened from the inside so when you get out and shut your door they are locked with no alarm. The immobiliser will still activate.

[MajorClanger]

quote:
One way, the way a lot of people get locked out is too lock the doors from the inside, they will not unlock until both doors have been opened from the inside so when you get out and shut your door they are locked with no alarm.

I tried that. The doors won't lock from the inside without the ignition key in and (as a safety feature) unlock when you turn the ignition off. Thanks for everyone's help.

Having spoken to the TVR Dealer in Heathfield (Thanks Ben) it sounds as if this is not an uncommon problem. As the car is going in for a service next week they'll check it out then. Part of the problem is the location of the siren/alarm control box making it prone to water ingress and damage. As a short term measure the power supply to the siren can be disconnected (a plug in power lead) maintaining all other alarm features (i.e. ability to lock doors, alarm sensors and flashing lights). The battery back-up in the siren will still mean that the alarm can sound several times before it's exhausted but at least the neighbours will get some peace and quiet eventually!

A final thanks to the thoughtful neighbour who couldn't be RRRRRRsd to tell me that there was a problem with the alarm, making it sound a lot worse than it was, informing the environmental health officer (poor guy sat outside my house for an hour without the alarm going off once!) and giving him misleading information. All credit to the EHO, a very considerate fellow, very understanding and sympathetic.

PS do you think it would be unfair to mow my lawn on Saturday morning with my silencer free petrol flymo?!!

MC