This is meant to be a supplement to this DIY
, which shows how to glue the female end of the connector back together, but does not help if the whole locking lever is broken; and also to QSilver's excellent repair DIY (referenced below.)
The seat switch module controls the forward/backward movement of the seat itself; the movement of the backrest; the movement of the headrest, and the movement of the steering wheel. Because of a poor design, if the plastic trim piece that surrounds the seat becomes loose (see below), then the female and male ends of the module separate. Eventually, the female end breaks...or the locking lever breaks...or both break, and the even the slightest movement of the trim piece will pull the two ends apart.
Result: no seat or steering wheel adjustment, and no seat memory function.
In my case, since the white locking tab was broken, even when I took the whole trim piece off and stuck the two halves back together, the two ends would work their way loose.
Thus, I wanted a permanent fix that did not require replacing the connectors.
Remove the seat adjustment buttons. Use a wide flat blade screwdriver to pry them straight off. Or a damp cloth to pull them off.
Remove the two #30 Torx screws, one one the front of the trim piece and one on top (borrowing these images from QSilver's writeup on BimmerforumsDIY
The issue with the one on top is that it's not accessible unless the seat back is reclined, which is impossible if the switch is not working. So, you may need to remove most of the trim section, press the halves of the connector together until you have power, then recline the seat back and remove the screw.
Step 3: Remove the plastic rivets, of which there are three:
Be careful to keep them intact.
Here's an image of the male end with the broken locking lever. Once this piece is broken, there's no easy way to repair it:
Here's the female end, with the standard broken part:
I placed the broken section of the female end back where it belonged, connected the two halves, then wrapped the entire thing tightly with electrical tape:
After that, I clamped the whole thing together with a zip tie:
In my case, I had another problem: the metal tab at the front of the trim piece that the front Torx screw held had cracked and disappeared: this was the reason the trim piece got loose in the first place and caused all the trouble:
My solution was to glue a washer on this area with Gorilla Glue and then put the Torx screw through it, then tighten it down:
I'm not totally convinced this will hold forever, but it beats buying an entire new trim panel.
Of course, my neighbors started making cracks about "fixing my fancy BMW with Gorilla Glue" but hey, whatever works!
Put everything back in reverse order, then press the switches back into place.
Now, even if the trim piece comes loose, the two sides of the connector should not separate; there's enough slack in the wiring for a little play, should the loose trim piece pull on it a bit.
That's it, hope this helps someone else.
Thanks to Q for the excellent write up.