I am in the process of changing all 4 of my oxygen sensors and I need to cut the wires but I'm not sure which wires are heater, ground, power? Can someone please help me out. There is 2 white wires and 1 black on the 3 wire O2 sensors and 2 whites,1black,1gray on the 4 wires. Thanks

 

i take it you bought the universal sensor to save some money huh okay well ground is black the wites are both signal wores so use whichever just not both of them and the heater is gray make sure you ziptie your conncetions and be sure to make your connections tight and secure and use plenty of electrical tape around each wire connection then over the whole bundle

 

I just replaced the first 2 sensors yesterday. On the 3 wire, the 2 whites are the heater wires. It doesn't really matter which goes where. Just white to white. The black wire is the signal wire. There really isn't a power wire technically. It is only 2 heater wires and a signal wire.
On the 4 wire, the grey would probably be the ground.

 

slinky87 said black=ground, white=signal, gray=heater
mikey... said black=signal, white=heater, gray=ground
??????????????????????? which one is it?