extending my 02 sensor because it wont reach the highflow cat.. i cut the wires and didnt notice tell afterwords that there is a green, blue, and 2 BLACK wires.. are both these black wires ground? i dont want to mix the two up and **** something up. please reply asap

 

The black wires are the same.

You can switch them around and it doesn't make a difference.

 

thanks

 

One black is for the ground for the sensor the other for the ground for the heater element.