Symptoms: when opening the doors (whether with remote or central locking buttons) the door lock opens, but the button doesn't go all the way to the top (the distinct "click on open" is missing). Upon attempt to lock the door, the button stays up, the lock doesn't engage, but alarm system arms. Open the door, alarm blares. So far, I've always managed to get the door locked by cycling the locks open/close a few times (until I hear "click on open"), but that's not normal. I'm wondering if this is the actuator going bad (like here: http://bmwcca.org/forum/showthread.php?t=4341), or is there a chance that the black sticky goo finally got the the button rod after all these years (this happened on one of my previous cars, all it took was just thorough cleaning)?