You have to figure out which wire is which............
2 wires are for the heater (most likely same color)
The other 2 are the O2 sensor signal wire and the sensor ground.
The sensor ground is probably connected to the shell...........
Connect sensor signal to existing 1 wire. Sensor ground to good ground.
For the heater wires, connect 1 to ground (not in same place as sensor ground) and other to 12v ignition source.
Awesome. I will try that.
Am I correct that the harness coming off the 1985 SR5 pickup is indeed 1 wire? The previous owner clipped off the original connector on the harness side and installed a female electrical connection to the O2 sensor side that still has the connector. When I stripped it back to extend the harness for the new position of the O2 sensor, it looked like it was 1 wire. But I couldn't tell if the insulation was part of the wiring or not.
