I have a US spec 1993 300E with factory alarm installed. (has worked well till now)



yesterday the alarm on my benz totally flipped out on me while driving(started sounding the horn,flashing lights) after pulling over and attempting to turn off the alarm using the key, i was surprised to find out that the alarm could not be disengaged via the key at either of the doors nor trunk. (the little red light on the dash is constantly blinking)



i plan on trying to fix it if possible.



Could someone please tell me does the factory alarm have any relays that could be causing the aforementioned problem? if so , where are they located?


any other suggestions ?


thanks in advance

The control unit is most likely the culprit and its under passenger footwell carpet behind a cover.

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On my 97 SL320, ( which uses a later system that may or may not be similar to yours. ) the alarm would not always deactivate when I unlocked the door with a key. I ended up unplugging the RCL module ( Remote Control Lock ) to prevent it from sending a signal to the ATA module ( Anti Theft Alarm ) that one of the doors was opened. The RCL is tied to the IR remote key code so you can't just swap modules from car to car.

On the SL the, the RCL and ATA are in the right side of the trunk, near the fuel fill tube.