A/C PROBLEM
 

Hi everyone, I am trying to fix the A/C on my 1983 500 SL euro. I am told that the A/C is called a "Klima" system.
There is a Regulator below the dash that controls the system, and has the following ID# 1-147-328-020 and 000-822-0703.
The regulator has a 12 pin plug that is connected and appears to be OK.
There are also 3 other pins that are numbered 1,3,&4.
These 3 pins are not connected and there is no 3 pin plug close by and no loose wires.
Can anyone tell me where each of the 3 pins are connected to from the regulator.
Thank you.