Driver door lock not working. Please HELP!

[Juanca]

Hi after reading about 700 posts I couldnt figure out what is wrong with my 1995 c280's driver door lock. It wasnt opening or closing with the pump vacuum system, if i push it down it will go down and it will go up if i open the door and it is annoying to have to lock and unluck the door from the passenger side. so i decided to open the door panel and I found the yellow line that comes from the pump but it is unplugged! And there is absolutelly no where to plug it in.

Ps. I have to add that I have had the car since new and this happened after I took it to a tire change place when I was on a trip, they gave me the car with the new tires but the drivers lock stopped working.
Do you think that someone stole an important piece from the door's mechanism? Or am I missing something? Cause I just cant figure out where to plug it! Please help!