O2 sensor wires

Has anyone tracked where the 4 O2 sensor wires go? My plug is shot and I am thinking about redoing it, but would like to start at the begining.

On my '96, the wires travel up to the front of the engine bay, then get wrapped up with the injector wires running from the front to the back of the bay, then around behind the engine on the firewall. Two wires are grounded on the engine block, passenger side, above and behind the distributor, or below the #4-#5 cylinder spark plug holes.

The other two wires, presumably, make their way to the ECU and/or PCM.

I know this much, just because I had a wiring problem with my upstream O2 sensor. The eyelets on the ground-wires I mentioned were partially broken off right at the point on the engine block where they were supposed to be grounded. As a result, I kept getting a CEL. Funny thing was, the CEL didn't come on until I removed the OEM sensor & replaced it as a matter of routine maintenance (thinking I might get better gas mileage). From that point on, it didn't matter what brand of sensor I used, or even going back to the crusty old OEM one, the CEL would always come back on.

I tested the wiring myself but couldn't find the problem (I didn't check the ground wires closely enough), so I wound up taking it to the stealership. It still took them 3 days to figure it out. Fortunately, they discounted the 3 hours of labor & didn't charge me for the parts (new eyelets & a little bit of soldering).

thanks for the info. I wonder if the are in the same place in my 98??? I will check tonight.