introduction

Good evening, I'm Klaas from Holland and I have a 450SL from '73. I like to work at that car, but miss some information, till I found this great site. Thanks for all the work you put in this site!
The engine is idling rough when hot. 
I have the feeling that something is wrong with the temperature. The meter on the dashboard never indicates more than 65 degrees Celsius. Can anyone tell me which sensor in the photo transmits the engine temperature to the ECU? And which sensor transmits the information to the meter on the dashboard?
Thanks in advance! 

- wrong information deleted -
ECU sensor was marked correctly.
The other I marked is for the fan.
See below.
Sorry.

Regards
Norbert

edit:
Welcome to the forum, Klaas!

Thank you, i forget to ask the third sensor next to "ECU"?

...That´s wrong, the round Connector is for the Fan in front of the radiator! For the dash  the sensor is in the Head at cylinder 4 !

Thank you, Christian, for the correction.
Will edit the wrong info, if possible.

Regards
Norbert

Klaas wrote:

Thank you, i forget to ask the third sensor next to "ECU"?
 

This is the thermo-time-switch that activates the cold-start-valve.

No error. This is true.

Regards
Norbert