Anybody who has done a DD install, have you had problems with the Nissan harness not providing a good ground? This is driving me nuts...

I've done a search on this... at least with the good keywords I could think of. I'm using a Scosche NN03B adapter, and it seems like all the pins are good, except that the "ground" (black wire) has a Vdiff of about +5v!! Using the harness ground as ground also causes wild fluctuations in the ignition and constant +12v lines. Not good.

I thought something was shorted so I removed the Scosche harness and found that probing from the Nissan harness side shows the same thing (I think ground on that side is a gray wire with green stripe?). No good ground on the harness either. Plugged the stock radio (non-Bose) back in and it seems to work okay though, which I think is odd.

Anyone?