Do it yourself, replace the battery on your Audi A4 B7 factory in year 2004, 2005, 2006, 2007, 2008, 2009. To make this particular repair, you will require a 10 mm socket wrench and a 5 mm hex wrench, most probably with an extension. We always recommend you to wear gloves, as the battery can be corrosive and dangerous. The process is very simple, if you follow the steps we show you next and you wont’t loose more than 10 minutes to do it.
At first, you have to open the hood and locate the battery. Use the 10 mm socket wrench, go to the battery and remove its negative cable, first. It is coloured in black, or you will recognize it if you look for the “minus” symbol. Then, you will have to detach the positive cable. It is, in most cases, coloured in red (as shown in the next image) and it is marked with the “plus” symbol.
In the final, you have to remove the bolt of the battery holding mount (you can see it marked in the picture below). In order to do that, you may need an extension for your 5 mm hex wrench.
At this point, you can replace the battery on your car. To finish the whole repair, just reverse the steps detailed above. Always remember to clean the terminal cables before reinstalling them, using a piece of sandpaper. This will remove the corrosion and will ensure good contact. At the end, connect the positive cable first and then the negative one, install the cover above your battery, if there is one, and you are done. This is all you need to do in order to replace the battery on your Audi A4 2007.