Try to trace the white wire that leads to the o2 sensor by unwrapping the harness that is in the vicinity of the o2 sensor. Try to fiind the wire that way. That's the way an electrical shop would do it.
Resplice the wires together. You've done most of the hard work. Good luck to you.
T
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Oxygen (O2) Sensor
OPERATION
All Fuel Systems
Fig. 1: A standard oxygen (O2) sensor, as shown, is used in all fuel injection system covered in this manual
Fig. 2: On non-turbocharged engines, the oxygen sensor (arrow) is mounted in the exhaust manifold
The oxygen (O2) sensor is a device which produces an electrical voltage when exposed to the oxygen present in the exhaust gases. The sensor is mounted in the exhaust manifold or turbocharger outlet and is electrically heated internally for faster switching when the engine is running. When there is a large amount of oxygen present (lean mixture), the sensor produces a low voltage. When there is a lesser amount present (rich mixture) it produces a higher voltage. By monitoring the oxygen content and converting it to electrical voltage, the sensor acts as a rich-lean switch. The voltage is transmitted to the engine controller which changes the fuel injector's pulse width. The injector changes the mixture.