Looking for someone who has run across these weird symptoms and could possibly steer me in a direction of repair.

Car: 1993 400E
Symptom: While locking car in drivers door, holding the key longer makes windows go DOWN, unlocking they go UP!
When unlocking, have to do it a few times for the alarm to disarm.
The alarm lite on the dash only comes on when unlocking and never when locked.

Would very much like to have system working as it should.
Help,
Tobias MB
4 MBs