The engine's vacuum pump has NO connection to the locking system on the W124. The electric vacuum pump and the vacuum lines for the door locks are isolated from the engine. The problem is either with the pump or the wires in the lock cylinder. First of all, do the locks operate when using the key in the passenger's door or in the trunk? If not, the culprit is most likely the pump. As you mentioned, there are two harnesses on the pump. One is red and brown, and another is blue/green/yellow. The red wire should have 12V constantly (always hot), and the blue/green/yellow wires receive 12V or ground depending on which front door or the trunk is (un)locked. While 12V is applied to the red wire, apply 12V to either of the pins corresponding to the blue/green/yellow harness. The pump should run as long as the wire is touched to it. While the pump is running, put your finger over the vacuum connector. It should stop. Now for the pump to run again, apply ground to one of those terminals. It should run.