Ok so I have a 350z that has been sitting for a while (blew the engine). I dropped another engine along with the harness and ecm. I took the car to a dealership to have the it reset to work with my key, but the ecm is getting no power. The fan kicks on as soon as I turn the key to acc. There is a long wire with a plug in the end on the driver's side of the engine. It comes out right by the maf and I have no idea where it goes to. I believe I read somewhere that the ground for the ecm fuse was by the airbox, and that is where this wire is at. I was wondering if anyone can confirm that and possibly tell me where it plugs in. Thanks!
That picture is not of my car but you can see the wire a whole lot better on there. It is circled in red

 

ac compressor clutch

it is a single wire connector and has two spare wires bundled with it.

 

Alright thanks! I am stumped as to why my ecu is getting no power. All the fuses are fine

 

the ecu fuse is behind that battery. if that is fine, you are gonna have to pull apart the wiring harness and back trace the connections