I have a 2007 Dodge 2500 with 6.7 diesel and 6 speed auto. On the driver's side, there is a wire that looks like it should hook up to the battery (+/-?). I found it unconnected. It comes from a harness down on the driver's side of the engine block just to the right of the ecm. Anybody know what this is. It's a black wire about 8 guage I'm guessing.

 

Take a photo would be glad to help you. It could be a ground wire for the PCM but check first for power and try to follow it to its termination point. There is two ground wire on the PCM located left side engine block they connect to a studded bolt that secures the PCM on the engine. Ground wire attaches at the Red triangle location. The wire will go up to the negative battery terminal.

 

Thanks BigIron. Haven't got a pic yet. There is a bundle of wires that is right above the red triangle in your picture. The wire I'm talking about comes out of that bundle. The bundle of wires goes a few different directions so I can't trace the wire. Any thoughts.

 

If it is black wire most likely a ground. Put ohm meter on it if 0 resistance to ground then a ground wire.