This may sound stupid...no, this does sound stupid. But I'm asking around to see if anyone can tell me just how the "AUTO" light on the headlight switch works - not what it does, but when it should be lit.

On my used 2004 A4 Cab, I've kept my headlights on "AUTO" consistently. Unfortunately, the indicator light isn't consistent at all -- there are times when the "AUTO" switch is lit. Most of the time, it's completely off. There are also times when it seems to blink intermittently. The headlights themselves always work flawlessly when AUTO is selected. And, to top it all off, this feature doesn't appear to be well documented in the copy of the Audi manual I received.

I humbly ask for guidance.