Hello! i have not been on this site for quite some time. I decided to keep the smog pump unplugged for now on my s class. I am now deciding that I should tackle this problem will my smog pump. So from what I have found, there is no electrical connection to the smog pump relay switch so the new switch that I have added makes no difference. However, my pump still works when plugged in, and does not turn off if the car is running.
My car is a 95 S320, made in the late part of 1994, W140 inline 6.
Martin, I will try to do what you said about disconnecting the airpump solenoid and see what happens. It will probably wait till I figure out my other, new issue (no connection to this).