xboxhaxorz

So over the past 3 wks my siren just starts going off, when im inside the house, right next to the car or even in bed. It goes off weather the alarm is protected or unprotected. Using the remote lock and unlock functions still work but does not turn the siren off.

The only way i can get it off is too unplug the battery for about 20 mins. I have tried disconnecting the main cable from the brain and even the relay as well as other random cables but it does not turn the siren off. My backup battery/ siren is disabled with the key, as 2 sirens going of is hella loud. But it still does go off, i had a shop look at it and they could not find anything wrong.

Fabrik8

You probably have a loose connection somewhere, or a fatigued solder joint on the alarm brain. Electronics don't just fail for no reason, and the siren doesn't just go off unless the alarm module gives it power. Have you checked to see if there is a problem with any door switches, pin switches, etc., that are connected to the alarm as triggers?

xboxhaxorz

But if i disconnect the brain, shouldnt it turn off? I think i only have a shock sensor nothing else sets it off unless i hit the car

EH3_SOHC

that does sound very strange. a backup battery will keep the siren running if the main battery is disconnected but if the brain is getting no power then theres nothing to provide the signal to the sirens. very weird. brain may be bad tho, bad solder joints or if you have a proxy sensor it might be that too.

xboxhaxorz

Well its a backup siren/ battery but i have the siren on the backup turned off but it should still provide power to the other siren, but thats not important right now.

If it was the brain, when i disconnect the battery, unplug the brain and then reconnect the battery the siren should be off, but it still stays on.

Since i disconnect the brain after the siren goes off, shouldnt that disable the siren?

EH3_SOHC

why dont you just track the red and black wire from the engine bay to inside of the car to see where the wires go. they should go to a brown wire on the main harness of the alarm(to the red on the siren) and the black is a ground and let me know what you see.

xboxhaxorz

i followed the wire and found it was connected to the backup siren battery. i disconnected the red wire to the siren because it went off again and since u told me which wire it was i cut it. a few hrs later, the backup siren started going off in a lower tone, i double checked if it was off with the key and it was, when i turned it on the siren got way louder and back off again it was a low siren.

i disconnected the main battery and cut the black wire to the backup siren and reconnected the battery. no siren, im gonna say maybe the backup siren is defective which triggered the other siren and thats why i could never figure it out. but it was weird that it came on even though it was off.

i will check other wiring as well and post back if it comes back on or is fixed

xboxhaxorz

yep, i believe that was it. hasnt gone off. thanks for the tip

EH3_SOHC

no prob man, its what i do.

2nd one

what kind of car is it. fords factory setup sends a pulse on the door triggers every 30 mins as a self test. that change in voltage trips the aftermarket security unless it is diode isolated.