I finished a stereo install late last night. Install was long & arduous, with a few headaches. Man, that "A" pillar cover is a bear. Hope I never have to take it off again. Anyway, the DIY video provided by Enfig for the A3 was great. Everything is working fine, even the remote USB ports.
Strange thing happened, though. This morning I went to my to check on the head unit functions. While I'm sitting there after about 15 mins, the "low battery" warning comes on. I was in the midst of running a software update on the head unit. While it's going I hear the engine cooling fans going full bore. I hadn't even started the car. The fans didn't stop until a minute after pulling my key from the ignition. And now? Battery is dead. Can't start car.
Last night I did use the cabin light for a couple hours. Yet the car started up OK. I'm seriously hoping this head unit isn't putting a draw on the car's electrical system while the car is off. But I'm really baffled as to why the cooling fans were running. I'm thinking this has to be a coincidence. I only dealt with the head unit wiring harness, nothing else. Anyone else here experience this?
EDIT: It all cleared up after the jump start. Seems that if the battery is very low, the fan relay can get triggered somehow when engine doesn't even need cooling. After driving for a good 20~30 mins, everything is OK now.