Frankly, I don't know what he's talking about. The O2 sensor comes with a cable that has a connector on the end of it. You disconnect the cable or wiring, unscrew the old sensor, screw in the new sensor and plug it in the connector. Done! If which one is bad is a mystery then you switch them side to side to see if the code changes. Pretty easy stuff. Perhaps the wiring is melted? It's clipped up out of the way and protected for the most part. Confused. You need a detailed explanation of what the problem is from the mechanic.

Les