Now I have done this job, I am looking closely at the infamous BLUE clip.

This is how I think it works:
- Press on the clip in the areas as shown (RED arrows)
- The BLUE clip free ends are fixed inside the connector, so they don't move much but the upper part should expand OUTWARD (BLUE arrows), allowing you to undo the connection.

However, this is easier said than done, it was a struggle for me, so whatever you do, stock the Dorman clips beforehand!

Attached Images

 

__________________
1998 E39 528i 5sp MT
2006 E53 X5 3.0 6sp MT