oh man i was browsing through the threads and found this and had to read it. i used to own an older audi that had the same problem after a audio company installed my new stereo. it was a big mess! at first my car wouldn't start unless my seatbelt was clicked, than in wound down to a ghetto security feature where you had to have the shifter in the right position to start it. there were only 2 people that could find it that sweet spot, my dad and myself. so sorry you gota go through this. but to answer your question, on my audi the switch was under towrds the front of the little gear indicators from what i remember. it should be arond there somewhere. its a switch to keep you from 1. starting your turck in the drive or reverse and i think it keeps you from thowing it in reverse while in drive. good luck!!
