Cluster confusion

Can anyone help, I've got 3 instrument clusters and these are the issues I'm having. 
So it's a 1983 gti and I have 2 mfa clusters (one vdo and one motometer). When either of these are connected everything seems to work, tho I don't have the oil led illuminating on ignition on, and the lcd screens work on both of these. 
Also to note, the led for oil light has been tested on both mfa clusters and they are ok. 

Now I also have the non mfa cluster from what I believe may be from a later cabriolet, with this one plugged in I get the oil led come on with ignition on and then turns off as expected on engine startup, however on this cluster the lcd screen goes blank as soon as ignition is switched on and stays off on engine running, (I've also tried an identical set of this type of cluster and same thing) 

Earths have been checked and are good. 

Would anyone know if there is something that I may have to do to the 14 pin connector I.e swap any wires around to solve the issues on either the mfa or non mfa clusters? 

Thanks

If you take off the Shroud of the main connector, then remove the Mylar off the tongue, with a piece of white paper on the back side you can see what the Germans called every pin.





Take one of each off and see if the pins match.
If they don't you can move the pins about by lifting the latch off the connector and bending the keeper bar back.  Have a Bentley or Haynes handy if you didn't write the wire colors to the pin locations down.

Now before going back.

Place a strip of electrical tape pad side of the tongue.


Splice in a frame ground to pin 2 brown.




Should be good to go, I also usually change all the lamps as I don't want to go back in there again.