I've done some digging. The CD service manual has the 380sl and the 560sl. This car is a euro 500sl.
I looked at the removal/reinstallation section of of the throttle assembly of an 86' 560sl.
I see in the picture the switch would be on the right side of the throttle assembly when facing the car, directly opposite of where the throttle linkage connects.
There is no switch on this car. I see the two holes where I believe the screws that would hold the switch on would go and it looks as though there is a plate/plug in between.
I read on one of the testing procedures "Vehicles with throttle vavle switch". This would lead me to believe that some models did not come equipped with the throttle valve switch.
If this is the case, and this car never had the throttle switch, would you agree from my previous testing that my problem is the idle control unit?
I appreciate your help.
1983' SL500 euro