I beleive you have a problem in the central locking system. You will soon experience the doors locking by themselves and it may even lock you out. My trunk lock/actuator assembley is going bad. The car sometimes locks when I hit a bump, slam the door, etc. When this happens. I get a close encounter of the third kind. The headlights and taillights begin to flash and they wont stop until you lock and unlock the drivers door with the key.
Well I got the lights to stop flashing by disconnecting the wires to the alarm system, under the passenger floor panel. I decided to disconnect the alarm after reading a post with the same problem. I was easy. I set off the alarm by setting the alarm and opening the door standing outside the car and opening the driver door using the inside door release (window rolled down). The alarm would go off and you can hear the system tick like a bomb. Then trace the wires under the passenger floor panel and find the wires that it takes to shut it down.
1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T