Thanks for confirming,
andrewwyn.
The cap I'm talking about is the factory dust cap that fits onto the 20-pin connector. Inside this cap there are jumpers and unless this cap is on the 20-pin connector (locked down) the inside 16-pin connector is dead.
If your cap is missing, then as
andrewwyn suggested, you will need to jumper a few of the pins on the 20-pin in order to get the 16-pin functional.
Have a look at this thread...
https://xoutpost.com/bmw-sav-forums/...-icarly-2.html