I have a 2003 S-80-T6 looking for wire colors from ecm to 02's (Downstream) I have to replace a bad wire for the heater on a 02.

 

Nothing?????????

 

why would you not replace the sensor along with the complete wire to plug in by the fire wall - how do you know its the wire and not the heating element? All O2 sensors are pretty much the same with the exception of the harness length and connector. This vid may help, or you can get hits by googling "O2 sensor wire color code"

 

I tested my 02 and found I have a bad ground at the socket for the o2 heater.
all 02 are 2 years old