door and trunk vacuum works only a few times after reconnection. on 1998 Mercedes-Benz S500

vacuum pump that located in the trunk works only a few times after I disconnected a connector and connected it again. All doors and trunk losses vacuum one after another. I though that vacuum pump creates the problem therefore I replaced it with a new one. But the problem is still occurs. Thank you.

Asked by for the 1998 Mercedes-Benz S500
have a smoke test done on vac system to determine if you have a leak to start with
thank you!
1 more answer , 1 more comment
possible leak in vacuum system
how to check it?