Volkswagon Audi Relay, part number 4D0 951 253 / 372. This is a genuine OEM part, not the cheap aftermarket stuff. The relay has been thoroughly bench tested prior to being listed for sale. We use a digital multimeter (DMM) to test the resistance between each pole of the relay and the corresponding NC and NO contacts for that pole. All NC contacts should read infinite resistance to the corresponding pole. All NO contacts should read 0 ohms to the corresponding pole. We do this procedure for each and every relay we list for sale. Most relays will outlive your vehicle, however, when one fails you can count on us to deliver a certified product at a fraction of dealer cost. Please contact us with any questions that you may have. We offer free shipping on this item and a full 1 year warranty.