VSS wire for 2000 Mercedes E430

I have added a Kenwood video head unit (KVT-911dvd) with navigation (KNA-2100) to my 2000 Mercedes E430. I have taken it to several radio installation shops and no one can locate the VSS wire for the navigation system. They are telling me that I need a canbus adapter to convert the signal from digital to analog. Can anyone tell me where the VSS wire is located and if a canbus adapter is the solution. This adapter is $200 and I don't want to spend that if I don't have to.

DEI wrote: Speed Sense GREEN/ black      radio harness

Do the shops realize you are talking about a 2000 mercedes?Certified Security Specialist

Always check info with a digital multimeter.

I promise to be good.

Tell Darwin I sent you.

I've been sick lately, sorry I won't be on much.

Yes.  They have tapped that wire and still nothing.  I don't know if that is giving an analog or digital signal.  Maybe my car is giving a digital signal and the kenwood nav will only recognize an analog signal.  I guess that is why the are recommending a canbus adapter to convert the signal.