The battery in my 2005 was old, dying, and not holding a charge. I confirmed this by taking it out of the car and charging it overnight, letting it sit for a day and testing. It would drain without any load.
I am attempting to trade the car in this week, so I bought a Duralast Red Top from Autozone in the same size as the stock Audi battery. After installing, the car starts and runs fine, radio works, car locks and unlocks, but the hazard lights will not stop flashing. Both front and rear flash rapidly until the battery is unplugged, and continue to do so for a few seconds after that. A quiet alarm sound comes intermittently from the right rear of the car. Pushing the hazard light button causes the hazard light blinking to slow to about half the speed it does otherwise. When the hazard light button is turned off, they speed up again.
I have no idea what this is, and have not been able to figure it out searching on Google, Audiworld, here, or Audigeeks. I called an Audi tech who said he had never heard of the problem before.
Has anyone seen this? If yes, how was it remedied? Any help would be appreciated. I have a sneaking suspicion that the dealer will low-ball me on my trade-in if I bring it in with the hazard lights going wild.