I am in the process of connecting the Metra wiring harness and the wiring harness that came with my Pioneer AVH P4100DVD. If both the HU harness and the Metra harness have a ground wire, do both need to be grounded? Or can i just ground teh wiring that connects to the HU? If i need to do both, can i just tap into the HU harness ground? Thanks.

 

the metra harness plugs in to the factory one and all the wires coming off of it get conneted to the harness on the unit. red to red black to black and so on.

 

Rgr. So the black wire (ground) from the HU harness connected to the black (ground) wire from the vehicle wiring harness will result in the appropriate ground for the system. I just want to confirm that cant just ground the HU directly and not using the harness. THANKS.