Just an FYI. My daughter's 1990 300 ce anti theft alarm would intermittently activate opening the drivers door after unlocking the car. Culprit was the driver door lock contact switch. (makes sense, gets the most use) Replaced with a new micro switch from MB dealer ($145.00 eeekk!!), rather than disconnect alarm in passenger foot well, problem solved, and as an added bonus, capability to lock/unlock car from trunk station magically worked again! Must be tied together in the same circuit.