420sel alarm
 

hey all,

To my understanding all one has to do to disconnect the factory alarm is to pull one of the two plugs under the passenger footwell right? I did that months ago and my alarm hasn't worked since then. Last night, I was parking the car in the garage and as I got out the alarm went off for no reason. I tried to disarm it with the key in the door lock, but it didn't work. I finally got it to stop by turning the ignition into steering lock 2 position. It made the ML's amber lights start flashing too. So my question is, is there another reason for the alarm to go off, and for the ignition to disarm it? Also, does a 2000 ML320 have a silent alarm or what? It just flashed it lights, no horn. Thanks for any replies --john

check the plugs
 

If you haven't already. My E320 may be a bit different but the alarm plug had been pulled, by the PO I assume. I happily drove it all summer with no alarm.

But the bottom plug which is an assembled plug came apart. Hence all the wire pins were free to touch one another or the sheet metal. The result in my case was that the car thoght it was armed and alarm going off. The started was locked out and I could hear the ATA relay ticking like a turn signal but the horn didn't blow and lights didn't flash. In my case I reassembled the plug and plugged it back in and all is well.