IS YOUR MERCEDES ALARM WORKING ? - A simple test.

ALARM: Many previous owners disabled the factory alarm systems on these older Mercedes models due to false alarm triggering when un-locking the car with the key.The false alarms are caused by worn micro-switches on the door lock barrels, and usually there is nothing wrong with the cars alarm module.

If the alarm module was disconnected, you could try re-connecting it. If it was just the micro-switches causing the problems, you will be able to control the alarm with the Keyless entry and overcome the problem

So you might want to check your factory alarm is connected and working. Here is how: -.

With the car windows open, but the doors, hood and trunk closed, lock your car either with the Aussie Keyless Entry or with the key. Wait a few seconds for the alarm to arm. Then put your hand in the open window and open the lock by hand, and open the door, then put your key in the ignition and turn the key. By now your alarm should have activated by either the door trigger or the ignition switch trigger. (Headlights will flash, and loud Alarm horn will sound). There are also other triggers on the hood and trunk.

To stop a triggered alarm, un-lock the door, with the key or Aussie remote control.

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If you can’t start the car, and the headlights are flashing, then the alarm got triggered, but the large alarm horn has been disconnected under the hood. (Probably as the previous owner got fed-up with it). You should re-connect the horn under the hood, as there is probably nothing wrong with your alarm. It is situated near the ABS unit in the engine.

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If your alarm did not activate during this test, then your alarm has been disconnected or removed, or is not functioning.  Apparently on the very early models, the alarm was an option, so maybe your car never had one. You will find the factory alarm module under the foot well on the front passenger side. Lift the carpet up and you will see a plastic panel. Remove that panel, and it should be there. If the alarm system has been disconnected, it was probably un-plugged here.

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Another problem encountered with the Mercedes factory alarm is it will activate when you lock the car from the drivers door or passenger door or trunk. (You need to try them all). If this happens, you need a replacement alarm module. Used alarm modules are approx $25 at wrecking yards.

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