How to Replace a 2001 Audi A4 Tail Light

1. Turn off the A4. Ensure that the parking brake is on and that the gear selector is in Park.
2. Open the trunk by either pulling on the trunk release button beneath the steering wheel or by pressing the trunk release button on your key fob if you have that option.
3. Locate the oval panel on the side of the trunk wall. Pry the panel off with a flathead screwdriver, using gentle pressure to avoid cracking the plastic of the trunk. There will be a bolt head inside the cavity that was covered by the plastic panel.
4. Loosen the bolt inside the cavity. This will release the lens cover on the brake light on the rear of your Audi. Be prepared to catch the lens, to prevent scratching the lens or the rear paint. If the lens cover does not come off on its own, you can pry it off gently with a flathead screwdriver. Be gentle to avoid damaging the paint or cracking the lens.
5. Remove the light bulb from the electrical harness by hand. The bulb just plugs into the port--no special tools are necessary. Place the lens cover back on the tail light. While holding the lens up, thread the bolt back into the cavity by hand until it catches in the grooves on the lens backing. Tighten the lens down with a wrench, until the lens cover will no longer wiggle if you push on it.
6. Repeat this process for the other tail light. Turn the car back on and test the brake lights by pressing down on the brakes while someone else looks for the brake lights to signal.