Alarm goes off after an hour

[Rob_Willow]

I've still got this problem with my alarm. Orignally after twenty seconds it went off, turned out to be the bonnet switch, which I have temporally removed and taped together to simulate the bonnet being closed.
I set the alarm, and it didn’t sound after 20sec. I thought great its fixed. Later on in the evening it went off after say an hour?
I've no idea what this could be. I don’t think its the ultrasonic’s. Is the alarm sensitive to noise? My neighbour started his motorbike earlier and I’m sure it upset the clio.
The alarm is a sigma M30, standard on my 172


Plllz help its irritating me....

 

[nathanH]

next time it goes off check the red light down near the gearstick, if it flashes 3 times after the alarm has gone off (dont put the ignition on as it cancels it), then the alarm was triggered by the motion sensors, they are very sensitive from the factory, do a search, you can switch the wires round to decrese sensitivity but have to remove the dash top, also i found having a battery thats on its way out doesnt help. I take its a standard alarm.
you can also turn the sensors off, turn the ignition on and off twice and lock the car after 7 seconds, the alram will beep 3 times to tell you the sensors have been turned off.

nathan

 

[Brown.]

Close all vents and befor you leave the car switch the air con to recirculate ( or recyecle as some people like t call it)...... give it a try....or reverse the wires on the sensors.....one way its 80% sensitivety, the other 20%

 

[BrianR]

I've still got this problem with my alarm. Orignally after twenty seconds it went off, turned out to be the bonnet switch, which I have temporally removed and taped together to simulate the bonnet being closed.

....

I hope you mean you insulated the contacts so they were not touching ? or taped the switch closed.

You might find its still the problem, just disconnect it and tape the ends of the wires (separately)

 

[Rob_Willow]

I've cut the cable that connects to the catch, and taped it up. I presume the 12v black only operates once it touches earth, so yer i taped that up.

 

[BrianR]

I've cut the cable that connects to the catch, and taped it up. I presume the 12v black only operates once it touches earth, so yer i taped that up.

Thats right, the other wire is the earth, but it is actually grounded via the BMT.

 

[Stu_c]

i have got a clifford alarm mine seems to be doing the same sort of thing