Hello, with my Audi 80 (type B4) the ignition start switch (replacement part no. 4A0 905 849 B) seems to be defective, because with a temporary wire bridge (3 wires) made by the ADAC directly on the “counterpiece” (made of plastic) to the switch the motor can be started, and the electrical system works with it. Now I would like to replace the switch myself. I have already removed the lower cover, but have no idea how to switch the ignition start switch (approx. 25 Euro plus VAT) I have the original key (with lighting) as well as the flat spare key. I would also like to know if the lock is still to be used afterwards, otherwise I would also have to get new keys and door locks. The effort would be too high. Thank you for your tips! Greetings, AO