Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
The vacuum pump is also used for central locking. It might make sense to plug up the lumbar system vacuum connections on the pump, so that the pump would build up the vacuum there. But usually, the leaking connections are deactivated by the pump automatically if leak is detected. So it might be that vacuum pump is too weak and not building up enough vacuum, which will cause it running constantly.