I don't know how your locks stopped working, but a good sign that your vacuum pump is going out is that your door locks will lock / unlock very slowly. When I replaced my pump myself, they went up and down like lightning.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".