Just wanted to update this thread in case anybody else encounters problems similar to mine.
I thought I had fixed my problem by adjusting the position of my cable as it passes from the rear of the center console (see above). This worked for awhile, but my problem returned after a few months.
I ended up replacing the old cable with a new one ordered from Tischer. So far it seems to have fixed the problem, and my iPhone snap in adapter is consistently working properly.
As Hybris4u noted above, the replacement cable is shorter than the original, so you have to use a slightly shorter route to the trunk. Hopefully this won't adversely affect the cable (you must route it under the rear seat, and it might be subject to extra strain).
I imagine the original cable had some sort of short in it which screwed up its continuity. Since very few people seem to have been affected, I guess it was just a random manufacturing defect.
Hopefully the problem remains solved!
