So it occurs to me (and more than a few readers) that I neglected to give any details about the car in my last entry. Well, let's remedy that.
I bought a 2004 Audi A8L with 52,000 miles, which was relatively within my price range, and has the same layout and gear as the newer models. The downside is that the hardware revisions in this car are 3 years old, and apparently they made lots of changes in the interim. The other downside is the complete lack of warrantee, even though Audi recertified the car less than a year ago. Also, the nearest Audi dealer is around 50 miles away, and local shops won't touch this car for anything other than brakes or tires. In fact, the aforementioned problems with the garage door opener and light sensor were caused by a local tire shop letting the battery run down completely while putting on a new set of tires. After the jumpstart, those components stopped working.
So that's what led me to inspect the coding on the roof electronics module. This coding is standard base-8 additive, with specific values assigned to specific components. For instance, if the car has a solar sunroof, add 6, if it's a steel sunroof, add 2. If it has a garage door opener, add 256, and so on (the full list can be seen here). So I came up with a value for the roof electronics coding -- 4014. Inspection of this module with the VAG-COM software showed the coding was 4013, which is basically an impossible number. I changed that to 4014, and... nothing happened. I'm still feeling my way around the VAG-COM interface and capabilities, so I wasn't sure if an individual module reset was possible and I'd noted that even though I'd trickle charged the battery overnight, it was still showing only 50% capacity. Time for a reboot. I pulled the negative lead from the battery and replaced it a few minutes later. This powercycle fixed the battery level indication, and the roof electronics started working again.
When I was telling a non-geek friend about this, he was quiet for awhile, then asked how "a normal person" would have fixed this. The answer? I have no idea, but I'm willing to bet the dealer would have replaced the whole roof electronics module.
The other side of that coin was brought into sharp relief by Jon Udell, who emailed me this morning:
Here's hoping this query continues to produce zero results:
Then again, it would confer a certain sort of celebrity...