I too am trying to connect up my audio out from the Zumo 660 into the BMW Com System. I had to cut the wiring harness in order to be able to connect it to my BMW Wiring harness I previously used for my Street Pilot and then my 550. The headphone jack line (audio out) has four (4) wires: yellow, orange, brown and purple. Can anyone tell me what the various wires are for? I just want to come out with mono out of the GPS. I was able to do that on the 550 but I just can't seem to get it to work for the 660 wiring. Your help would be appreciated.