2003 E39 Alarm Issues

I've had this car since new, bought it in the UK and exported it last year when I emmigrated to New Zealand - anyway - thats all irelevant. I've had alarm issues on this one since new - and the dealers cannot find whats wrong. I'm going to try and disconnect this bonnet (hood) switch, if I can find it. One thing I have learnt to do to stop the alarm going off, is to get out of car, lock it, then unlock it and walk away. As long as you don't open any doors when you unlock it, the car automatically locks itself after about 2 minutes and the alarm doesn't go off. I've tried the old "double press of the key" to disable the interior sensors, but that doesn't work - the alarm still goes off. Not sure why the alarm doesn't go off when I do my little lock, unlock, walk away trick - but it has worked for me. Does anyone know if there are other sensors - i.e. in car parks it goes off so much - possibly when other cars drive by?

I unplugged my Hood (Bonnet) switch - and the alarm has not gone off since - switch feels a bit stiff (posibly corroded after shipping the car across the world in a container) - so removing my switch has saved me about $1,000 NZD since the dealer wanted to change the interior ultrasonic sensors!!! - thanks Bimmerfest for such a brilliant forum!!

Originally Posted by UKTONZMAT

I unplugged my Hood (Bonnet) switch - and the alarm has not gone off since - switch feels a bit stiff (posibly corroded after shipping the car across the world in a container) - so removing my switch has saved me about $1,000 NZD since the dealer wanted to change the interior ultrasonic sensors!!! - thanks Bimmerfest for such a brilliant forum!!

I had to pull the plug on mine last month also. It's a piece of crap. I've installed hood switches for alarms and they are tiny and simple and last forever. Why this thing is so big and such crap, I'll just add to my BMW mystery list.

Drive home. Park Car. Set Alarm. No issues.
Go to sleep.
Wake up in morning.
Put key in keyhole on drivers side. Turn Left to deactivate/unlock.
ALARM GOES CRAZY!!!
Turn key Right to re-engage alarm. All is quiet.
Turn key Left to deactivate/unlock.
Alarm is silent.
I get in and drive away...
No problems again until I reset alarm.

I have a little "key hole dance" that I do where I turn the key quickly from left to right back to left again (Disengage-Engage-Disengage) where the alarm will go off for about a half second before i disengage it again but I'm sure it's still annoying as hell to my neighbors.

Same issue with the key fob button. Alarm will go crazy until the keyhole dance is performed to appease the Bavarian Gods of Security.

Any help please??


(Found out if you hold key in that left "open/unlock" position for more than 3 seconds, all windows roll down. Sweet!)

I noticed something about a month ago about the hood alarm switch.

If yours is acting up...it may not be the switch's fault...it might be from the insulation on the hood. If you lower your hood slowly, you'll notice that the tip of the hood switch DOES NOT touch any of the exposed metal on the hood...but actually pushes up into the insulation on the hood.

If you look closely at the insulation just above the exposed metal section of the hood (where the microfilters would be located on the e38 7 series)...and it is worn away...this could be what's causing the hood sensor to false trigger the alarm siren. The switch may not be pressed down far enough.

Originally Posted by piscesbmw

drive home. Park car. Set alarm. No issues.
Go to sleep.
Wake up in morning.
Put key in keyhole on drivers side. Turn left to deactivate/unlock.
Alarm goes crazy!!!
Turn key right to re-engage alarm. All is quiet.
Turn key left to deactivate/unlock.
Alarm is silent.
I get in and drive away...
No problems again until i reset alarm.

I have a little "key hole dance" that i do where i turn the key quickly from left to right back to left again (disengage-engage-disengage) where the alarm will go off for about a half second before i disengage it again but i'm sure it's still annoying as hell to my neighbors.

Same issue with the key fob button. Alarm will go crazy until the keyhole dance is performed to appease the bavarian gods of security. :d

any help please??


(found out if you hold key in that left "open/unlock" position for more than 3 seconds, all windows roll down. Sweet!)

bump

I had a problem, or at least I thought it was. My German Shephard was in the bimmer and the alarm started going off. That is when I found out about the ultrasonic sensor shut off setting. Press the lock button twice and bingo, no shock or ultrasonic detection. I also like the window roll down feature, made famous by VW commercials.

Originally Posted by Warren928

I had a problem, or at least I thought it was. My German Shephard was in the bimmer and the alarm started going off. That is when I found out about the ultrasonic sensor shut off setting. Press the lock button twice and bingo, no shock or ultrasonic detection. I also like the window roll down feature, made famous by VW commercials.

I knew I wasnt the only one who saw those commercials . I like to make fun of them because BMW (and I bet some other car companies) has had that feature since the 80's

I have disconnected the hood switch and even disabled the motion sensor by holding the lock key for a second time after I locked the car. I still have the problem, at first the alarm will only come on for one bip then go off today in the morning it is little windy, and it is going off again. I have the newer motion sensor inside, is there any other switch other than the hood or the motion sensor? Is the hood switch normally closed so in other words the alarm system looks for the switch to be made when armed? Can I pull any particular fuse to disable the alarm but still lock the car? Please help

Originally Posted by coolrahul

I have disconnected the hood switch and even disabled the motion sensor by holding the lock key for a second time after I locked the car. I still have the problem, at first the alarm will only come on for one bip then go off today in the morning it is little windy, and it is going off again. I have the newer motion sensor inside, is there any other switch other than the hood or the motion sensor? Is the hood switch normally closed so in other words the alarm system looks for the switch to be made when armed? Can I pull any particular fuse to disable the alarm but still lock the car? Please help

I'm not sure if you've actually turned your tilt & interior motion sensor off by the way you describe what you did. You "press" the button twice, not hold it. Then you say that it is a windy day and the alarm went off...which could indicate that the tilt sensor was NOT deactivated....so let's do a quick test.

Roll down either the front or rear window on the driver' side. Get out and lock the door (the way you said you did by "holding" the button a 2nd time). WAIT 30 seconds, then stick your arms into the car and wave them around. If the alarm goes off, it means that you have NOT deactivated the interior & tilt motion sensor.

Unlock the door (to stop the alarm) and reset everything and this time...PRESS the LOCK button TWICE. Now wait 30 seconds again, and see if the alarm goes off.

Have you checked you car battery's voltage by doing TEST #9 (OBC must be unlocked)? A failing battery can also cause false triggering. Or the problem could be a failing alarm siren. It has a rechargable battery incorporated into it's design. If the car battery is failing...it will cause the alarm siren not to recharge properly. If the alarm siren senses a drop in voltage, it interprets that drop as someone trying to cut power to the car and will trigger the alarm. Or if the rechargable battery in the alarm siren is dying...the same could happen.

And if you've disconnected the electrical harness from the hood sensor...the system does NOT detect it or miss it then assume that something is wrong and set off the alarm. You can also disconnect the alarm siren itself...which is located in between the rear passenger side wheel well liner and the body of the car. You'll need to remove that wheel, then the liner to access it.

Originally Posted by TimeOut

It seems, I'm having the same issue now.

Last night, it was the first time my E39 was ever left parked outside overnight. Our garage is full of stuff because, we just sold our home and we're moving out next week.

It is a very quiet neighborhood and this morning with no apparent reason, the alarm just went off. I unlocked/locked the car with my remote and few minutes later, the alarm went off again. I again unlocked/locked the car and the alarm went off few minutes later.

I'm going to check the battery and hood sensor. Also, Is there a way to disable the motion sensor?

I have a '97 E39 and my alarm has been going off for sometime now. I brought it in to be serviced and was informed that one of the internal motion sensors went bad. Had the sensor replaced but the alarm is still too senistive and goes off anytime a loud motorcycle or truck goes by my house. I also uplugged the hood sensor hoping that this would do the trick but to no avail. I will try the double click.

I have intermittent alarm issues as well but an apparently different trigger. I have noticed that passing cop and taxi drivers when transmitting will set of the alarm. Anyone with same symptoms?

My alarm went off, i traced it to worn door seal, moisture tarnished contacts, solved by spraying contact cleaner into switch and pushing to work the switch a number of times, years since still ok.

I am having the same problem in cold weather on my 2003 540 and will try to disconnect hood sensor tonight. I just had it serviced yesterday so it's a bit suspicious it suddenly started happening.

However everytime it went of last night I noticed that when re-arming the light would blink rapidly, i.e. something is open. So I went around the car opened a door, re-armed, next door re-armed, etc and not until I did that with the trunk did it arm without blinking. 10 minutes later alarm would go off again and I repeated process to ensure the trunk would fix it.

Now I am inclined to think it is the trunk switch in my case, has anyone had this issue. And if so is the trunk switch easy to disconnect as well so I can test it tonight?

Thanks,

Mike.

on my 97 528i i have had the same problem with the hood switch and solve it. my new problem is when i lock the car i dont get a chirp from the sirene but when i unlock with either the key in the door or the remote the alarm goes into panic mode and its hard to shut down. now i have to manually lock the car. anyone ever had that problem b4

Originally Posted by trini4life

on my 97 528i i have had the same problem with the hood switch and solve it. my new problem is when i lock the car i dont get a chirp from the sirene but when i unlock with either the key in the door or the remote the alarm goes into panic mode and its hard to shut down. now i have to manually lock the car. anyone ever had that problem b4

Check your battery. The alarm acts crazy when the battery is going bad and unable to supply the correct voltage.

Thanks for the tip! I disconnected the hood sensor in front of the driver-side cabin air filter, and no more false-alarm problem !!!

I haven't had any trouble with the alarm going off while driving, although last month on 2 different occasions it just started going off by itself a few times while parked in the driveway. The first time it happened I took alarm fuse out and replaced it. The second time it happened I turned on the car, let it run for about 15 minutes, turned it off, locked my car and has not happened since.

Low battery voltage has been known to trigger most of these problems.

im experiencing the same issue with the random alarm being trigerred. Ive narrowed it to the hood alarm sensor. Just have to replace it I guess Or maybe grease it so it travels smoother and has no awkward sitting position when closing the hood.

Originally Posted by razzy530

im experiencing the same issue with the random alarm being trigerred. Ive narrowed it to the hood alarm sensor. Just have to replace it I guess Or maybe grease it so it travels smoother and has no awkward sitting position when closing the hood.

No grease....try flushing it out with some electrical contact cleaner spray. I would also examine the photo above and make sure it is fully depressed when the hood is closed. Otherwise simply replace it.

my neighbours and I will be really happy if the hood switch fix works - I will have a try tonite - thanks to all who posted

my alarm was going off all day several times a day so i removed the switch. so far so good....

ok removing switch worked like a charm

Same false alarm problem started for me a few days ago. Removed hood sensor plug and it's fine.

Thanks!