Diagnosing w124 alarm goes off on drivers door?
 

So I'm having a problem with my 88 300te where if you unlock from the drivers door it does not disarm the alarm so when you open the door the alarm goes off.

I purchased a used door alarm switch from someone on the forums that said he had no alarm issues on his car.

Installed it and still goes off.

If I unlock from trunk or passenger door it's fine.

Where should I look next? Or what can I test?
Anyway I can tell if it's still the switch or the control module?

If I am going to repair I would start by inspecting the wiring in the door where it "pivots" for a broken/bad connection.

Personally, I just disconnected the module when it started acting up.

I agree with engatwork on "disconnecting". Quite frankly, who would want to steal an old Mercedes? I had a '91 190 that had a funky alarm. One night in Sonoma at a motel at 3 in the morning..... Yeah it was me! Don't remember what I did to silence it but the next morning I found a local MB guy and had him shut the system down permanently.
However, my current ride is a gorgeous, black '97, S-600 coupe (CL600). I was told that this particular car is prized by the "capos" in the Mexican cartels so I am a little more careful where I park it.
Anziani
'97 CL600 51K