Theft deterent system goes off...
 

Hello all,

My alarm goes off from time to time when using the key to open the door (driver's). When it does, I re-insert the key back & give it a few turns to turn it off. My guess is that the key-opening latch that signal the control module to off has been worn to some degree. Any ideas as what/where to check. Is it easy to address ?

Thanks,
Frank.

My '86 300E does the same thing. It seems to be a not uncommon problem. It reached the point where I just disconnected the alarm horn and taped up the leads. Now I find myself driving down the road and noticing my headlights flashing on the back of the car in front of me. Oh well, It's better than having that damn horn blaring when I'm just trying to get into my own car!

On my car I've found that to turn it off, I just have to turn the key in the door lock one time all the way CCW. It shuts off just when it rotates to the extreme CCW position. I think I'm just not turning it all the way when I first unlock it.

I have an '94 E320 and the same thing happend to me. The technician sold me a $120 little harness that goes in around the lock. He told me that there is a hex screw on the door jamb and use that to loosen the lock. The lock should slide out with a little effort and he said that the new part was pretty easy to install. Mine has only gone off that one time so I haven't yet replaced it.

I hope this helps!

I too had problems with my factory alarm. After awhile of it going off spuratically, I just unplugged the module. The module is under the carpeting on the passenger side. If you take the mat up and the capet, you will see a black tray, Two wire harnesses connect at the top of the tray. Just disconnect the harnesses to disable the alarm.

I just replaced the driver door alarm harness--it wasn't too difficult. But, now the alarm still goes off periodically. I know that I could just unplug it, but this is a challenge that I have to overcome. Does anyone have any suggestions?

Thanks!
Cal Ratcliff

My car is doing the same thing ..87 300E and I also cut the wires to the horn..first time this happened in a year..:o