Missing 02 wire

[Dfather99]

1. Hello
   
   I have a 1995 k1500 ext cab. 5.7l 4x4.
   
   It is missing the purple o2 sensor wire. I've chased two purple wires from the fire wall but they appear to go to the fuse box.
   
   Can someone tell me what wire it is at the firewall so I can run my own wire and not cut the wrong wire. Or if u have a diagram.
   
   Thanks

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[koolbreeze]

My '95 K1500 w/5.7 & 5-spd has a 1 wire O2 sensor and the purple wire for it comes out of the main harness just above the left valve cover. The wire runs behind the engine towards the right side of the truck and my guess is it goes through the firewall right under the A/C accumulator and to the ECM.

 

[Dfather99]

Thanks,

I'll probably end up starting at ecm and chasing it all the way.