Ok my old headunit took a dump went out and got a new one. Now this new one will not power on unless I hook up the power wire(red) and constant 12v (yellow) on the stereo to the constant 12v coming out of the wiring harness.

There is no power coming out of the power wire on the wiring harness.
Yet my old headunit worked just fine. Went out and got another wiring harness thought something shorted out. Nope the new wiring harness has the same problem.

So b4 I go out and spent the $180 on a good access gmos-100 harness that keeps everything. Was wondering what the problem could be. The first headunit I had was like 6 years old. Would that have something to do with it working and my new one not.