Hi Cees,
Mine is located close to the main harness plug above the left knee as you sit in the car. Square looking relay type of box.
As I am fine tuning the engine idle, in and out of gear (working on things like the vacuum dashpot and need for a slight throttle lift when in gear...), I have to put the car in and out of gear (of course have the wheels blocked) and am constantly opening and closing the door. The buzzer has finally gotten to me... I guess this may be why it was unplugged?
Bob
bpossel (Memphis, TN.)
'71 280SL / '97 E320