Quick o2 question

[lotusgardener]

I just put in my test pipe and I think I kept everything kosher. Just in case, because I am about to do the diode mod, does the rear o2 use the black or brown plug? The DIY on Audiworld says not to touch the black plug, but his was written for an S4 it looks like.

This is on a 97 1.8t. Thanks guys.

[lotusgardener]

C'mon 30 views and nobody can pop their head under their hood for a second. Please people - I don't want to drive it if its off too!

[Seerlah]

Brown one is for the rear/secondary 02 sensor