Diagnosing w124 alarm goes off on drivers door?

[ps2cho]

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?