part # 165 906 381 or PA66-GF30. I removed the cowl, and removed the screws from the ECU lid, and the relay was right next to the ECU, but some people told me it was located under the ECU. My A4 is a 2001, and it is next to the ECU, in the ECU box. I know there are also relays under the drivers kick panel, but since this relay proviseds power to the ECU, you should be able to follow the wires to it.