I have a 1988 560 SEC and the door lock vacuum system does not work. That is I can only lock the two doors and trunk with the key.
I have replaced the vacuuum pump and know it is good. There does not seem to be a signal getting to the pump to turn it on. Any thoughts or experience on this would be appreciated. Incidently, could this be a grounding problem and if so where is the world would be the appropriate grounding post??