lock vacum pump

[Ahmad Helal]

on my 90.audi.100 my locks don't lock/unlock when I lock/unlock my my driver's door as it used to do. I just now heard of a lock vacum pump....where is this located on my car? would this be the problem or could it be something else?
 
-Ahmad
p.s. you all sound like great ppl..and I have had a GREAT expreince so far

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