DIY'd BMW alarm goes off on its own

F

Flycaster

Member
 Boynton Beach, FL
Three years ago, I DIY'd a BMW full alarm system into my 2005 Z4. Recently, the alarm has been going off by itself. After a couple of minutes it will turn off and leave my directionals blinking. I'm still under warranty, but I'm pretty sure that if I have BMW service look at it, they will charge me because they didn't do the install. Any suggestions as to what I can look for to fix the faulty alarm, before I try to do battle with BMW? Thanks.
 
99% of alarm problems is the bonnet sensor. Can you disconnect that for a bit?
 
Haven't looked at the connection in the bonnet for a while. But, I could disconnect it...is it just a simple pull the connector out?
 
You want to keep the connection open, so disconnect one wire.
 
Thanks, PVR. I'll give it a try. As I also have a motion sensor installed, I guess if anyone tampers with the hood (this side of the pond), the alarm will still go off.
 
If it is the switch, the replacement is about $15 at the dealers.
 
I was using the good old dollar rate of 2 - 1 :D Remember those days a few months back :wink:
 
This alarm thing is bummer. Yesterday, it went off twice while parked outside the tennis courts that were well in view. No one was near the car, the top was up, and I heard it right away. Over an hour ago, I set the alarm while the car was in the garage, Nothing's happened, yet. BTW, am I right in my assumption about disarming the hood not really affecting the overall alarm's functioning as a warning?
 
Almost always the interior motion sensor, there is always a way to disable this feature.Give it a go. :thumbsup:
 
You mean almost always from the remaining 1% that is not the bonnet sensor? :wink:
 
Hood switch disconnected. I'm not into disconnecting the interior motion sensor as that is a PITA. And, so far, with the hood switch disconnected, the alarm hasn't gone off inappropirately (BTW, on testing, it does work). However, this is still a tough one in that the alarm had been going off randomly...so, I'll have to wait a while to see if it really is the hood switch.
 
Flycaster said:
Hood switch disconnected. I'm not into disconnecting the interior motion sensor as that is a PITA. And, so far, with the hood switch disconnected, the alarm hasn't gone off inappropirately (BTW, on testing, it does work). However, this is still a tough one in that the alarm had been going off randomly...so, I'll have to wait a while to see if it really is the hood switch.
Click to expand...

Normally on most if not all aftermarket alarms there is a way of not setting the interior motion sensor.Usually set the alarm as normal with the fob then within a few seconds pressing the other remote button/ sometimes the same button, which allows the alarm to be set without the interior function on.This is used for example when paying for petrol whilst arming the car when people/kids are inside.
 
It is not an aftermarket it. It is a retrofit of the OEM system.

Disabling internal sensors on that is to lock the car twice, i.e. press the close button twice on the remote key.
 
Interesting. Haven't heard of this interior sensor control before. However, this is an official BMW full alarm system that I put in. Can anyone confirm if this approach works with the BMW alarm?

And BTW, it has been 24 hours since I disarmed the hood switch and the alarm hasn't gone off.

EDIT: PVR, thanks. Your post wasn't showing when I posted.
 
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