1988 W124 alarm question
 

Last night, the alarm went off on my 88 300ce. First time in 5 years. Never heard it before!:eek:

My gf and I went out and I think I locked driver door when we got out of the car. When we returned I noticed passenger door was ajar. As soon as I opened it (passenger door), horn started beeping and lights started flashing in intervals that lasted about 30 seconds with breaks of silence spaced in between.

I'm driving and she's reading the manual and finally I pulled over and reset the door lock on driver door with the key and it stopped.

Questions: Would locking the door, with one door remaining ajar (and unlocked) set up this potential alarm triggering condition?
Now that I've reset it with the key, it's in it's "operational mode"?
Once triggered, will the alarm ever go quiet without being reset with a key?

Anyone have knowledge of the workings of the system?

I believe it's covered in the manual. Talks specifically about the stages, and how long it waits before it shuts off. This is in '92 manual, maybe not in '88 manual.

Try having that happen at 6:30 AM outside a motel where you park outside your door. Woke everybody up. Had to jump in the car and drive off in a hurry.

The other thing that can happen is that the drivers door lock can wear out, which can trigger the alarm.

Steve
'92 300E

Thats funny. mine went off at 4am last night. not quite the wake up call i was hoping for...

i used to have a neighbor with a BMW and every time the temperature went below 35 degrees than darn alarm would go off! And yes, if you don't close one of the doors all the way after the alarm is set and go back and try to push the door closed the alarm will go off. Happened to me I almost wet my drawyers that thing is so loud!

Yeah, I jumped a little. Felt like a complete fool driving down the road with with the horn beeping. It is loud. Also, fwiw, it was 22 deg f by the dash outside temp indicator when it happened. But, she's usually home in the warm garage at night. (the car, not the gf ! She's warming elsewwhere;) )

I had locked mine differently last night. I usually do it with the key from the drivers door, but last night I pushed the knob on the pass side and shut the door to lock it. I also dont know if its someone coming around in the night and messing with the cars. One of my roomates has a protective order against this guy which has my property included on it so maybe its him. This is the 3rd time in about 4 years that its gone off. It always seems to be in the middle of the freakin night! 2-5am seems to be the magic window...

Any good way to dismantle it?........

yeah. unplug the module under the carpet

How was the alarm resolved?
 

1990 W124 (300E 2.6)

Recent purchase - getting to know the quirks.

Seems this car will set the alarm off 15 to 120 minutes after the door is locked.

How did yu resolve your issue?

Did you fix it or just unplug it?

Thanks

I'm thinking of replacing the driver door alarm component.

Yes, the W124 alarm is triggered by the same switch that turns on the dome light when a door is open. If the door is ajar and the slighest movement triggers the switch, the alarm will go off.


Yes. To reset the alarm you just simply unlock and lock the car again. Certain triggering situations requires that you turn on and off the ignition switch to at least position 1 (sometimes even position 2), but this is regularly required by more complicated alarm systems like the one installed from factory on W140s.


Well, it all depends on how it was triggered. For example, if an unauthorized entry is done by forcing a door open, the alarm will be triggered and will sound for 30 seconds, then it will automatically go off. If the culprit door remains open, then the alarm will go off again for 30 seconds periods with 1 or 2 minutes of silence intervals (the time it takes the system to reset from the first trigger). This process can continue until the car runs out of battery power, or by individual country regulation, on which legal regulation of how many times an alarm can repeat its cycle are limited (two, three, four or five times).

If the offending door is closed after the first trigger, the alarm will not sound again. In this scenario it is not necessary to reset the system with the key.


The alarm only sounds for 30 seconds (unlike some other systems which sound indefinitely until they are turn off with the key or an infrared remote control) due to general European legal regulations that determine that a car alarm on a public streets cannot sound for more than that period of time. Some countries vary this time limit (from 30 sec. up to 2 mins) but M.B. decided to cut it simple and set all their systems with the 30 second limit.

All doors, the trunk and the engine bay hood on alarmed equipped W124s should have pins that detect the opening of the offending device. Also, at least on Euro versions, the alarms sounds through a second horn which is hidding well within the engine bay and not the regular horns in behind the front grill.

Now, if we start talking about the W140 alarm systems (which they were three different types fitted), bring a cup of coffee and a comfortable chair...

Just go into the passenger footwell, lift up the carpet, and unplug the alarm module. There are one or two plugs (can't remember how many). Once disabled, you won't have to worry about it again. You can even throw your module up on eBay if you're not interested in keeping it. I'm not sure how, but those modules sell pretty well on eBay.