I must ask, did you check the wiring and components with a test light or volt meter while locking and unlocking the doors and write down the results?

A signal to the vac pump from either door lock and/or trunk lock will affect the pump in the same manner and it must respond regardless of where the 12 volts or ground comes from.

Also, the vacuum system is closed therefore if there are no leaks, all actuators must work when vacuum is applied unless one of the actuators is out of adjustment of broken/leaking/seized.

No offence or dissrespect intended but you sound like a "lawyer". It's a good thing that the car didn't have a more serious problem.

Labeling a a person "stupid" because he tried to unlock your car with the key you provided speaks volumes. These comments do cause reactions.

Lets stick to the problem, I repeat, did you check the wiring and components with a test light or volt meter while locking and unlocking the doors and write down the results?

Mine is a 92 300e so the fact that yours is a coupe may be confusing. Also Do you have vacuum operated front seat back locks? could there be a vacuum problem in his area?

Acky