Alarm problem

[felixbobcat]

Hi Guys, I'm having problems with disabling the alarm on my 96 850. The remote key will lock the the door by pressing the appropriate button but there will be no confirming chirp from the alarm when setting. If I press the unlock button the doors will unlock and the alarm will go off. If I use the the key to lock the door manually through the tumbler on the door, it will lock but when I unlock the door the same way the alarm will go off.

When tripped the alarm will sound for about twenty seconds and then shut itself off. I can start the car while the alarm is going off also.

The battery in the remote is about 8 years old so that should be replaced although it does produce a solid light when the the buttons are pressed.

Any ideas what could be causing this problem.

Btw it doesn't always have this fault. More times then not though. I live by LAX and I tend to have this problem close to home. Possible radar interference from the Airport?

[felixbobcat]

Anyone?

[Timm]

Are you sure there is no aftermarket alarm fitted? The integrated OEM alarm will not allow the car to start when the siren is sounding.....

[72tpik5]

Have you read this post?

https://www.bimmerforums.com/forum/s...=Alarm+problem

[llcarlos]

Isn't this a battery problem with the main batteries and/or the alarm battery? I was having the same problem with an M73. The alarm was going off for 20 seconds when unlocking the door and it was going off with the car just sitting as the security people phoned me about it going off. I forget if it would start or not before the 20 seconds was over. Part of the problem was I did not drive the car and finally after taking the car for a drive the alarm was no longing sounding but there is still no normal chirp when arming or disarming the alarm. So I think the alarm battery is the problem. The diff is leaking bad so I can't take it out much until that is fixed.

PS. the alarm was activating every time I unlocked the door. Since I took it for that one drive this summer it hasn't activated. I sometimes charge the main batteries with a charger but generally leave the car sitting until it won't start. It surprised me yesterday by starting when I hadn't charged it for a month. But there was no chirp.

[felixbobcat]

I believe the problem has been solved. Called a BMW Mechanic and told him the problem to see if he could fix it. He told me that alarm problems for the 850 are difficult to fix since new parts are now unavailable. He then suggested to try squatting some WD40 into the drivers door lock to lubricate it and possibly clean the sensors that activate the alarm.

It worked! The alarm now functions as it should, meaning its not being tripped when the door is unlocked. Also although the confirmation chirps are random. I sprayed some electrical contact cleaner in the lock after just to remove the WD40 from the sensors. Did all this yesterday and will have to see if the fix holds.

[felixbobcat]

Okay, Problem still persists. I guess it was too easy a fix.

[Budget M3]

I believe the problem has been solved. Called a BMW Mechanic and told him the problem to see if he could fix it. He told me that alarm problems for the 850 are difficult to fix since new parts are now unavailable. He then suggested to try squatting some WD40 into the drivers door lock to lubricate it and possibly clean the sensors that activate the alarm.

It worked! The alarm now functions as it should, meaning its not being tripped when the door is unlocked. Also although the confirmation chirps are random. I sprayed some electrical contact cleaner in the lock after just to remove the WD40 from the sensors. Did all this yesterday and will have to see if the fix holds.

I have a similar issue right now. While I have not been able to definitively resolve it yet, it appears to be related to an intermittently sticking lock mechanism. After the cars sits awhile (~1week), the problem returns. Using the key to lock and unlock the car several times in rapid succession loosens the mechanism and the alarm issue goes away for awhile. I don't yet know if the problem is mechanically within the lock/contacts or if it's the lock actuator or the power door lock module, but thought sharing my experience might be helpful. I'll be watching this thread to see how you end up resolving your issue!

[llcarlos]

Okay, Problem still persists. I guess it was too easy a fix.

With my diff problems I forgot to ask the BMW dealer about this alarm issue. Mine has not gone off since driving the car finally and when the batteries are charged the side markers flash strong when arming or disarming but still no more chirp. When the batteries are weak from the car sitting for a couple of weeks the flash barely happens but the alarm no longer goes off. Wish I knew more. Maybe it's the rechargeable battery on the alarm unit itself but that part is NLA.
The missing chirp is bothering me.