First off guys let me that I am glad I found this forum. It looks like a wealth of info here. This is my first post and I have a question about my o2 sensor. While out deer hunting this year, I somehow got a tree branch tangled up in my exhaust around where the o2 sensor is. Well it ripped out the sensor and the wire the sensor connects to. I have replaced the sensor but now I can not find the wire it is supposed to hook up to. What wire harness does the o2 sensor wire come from? How do I find the wire to splice it to the sensor? I thought about going to a junk yard to try and figure things out but have not made it yet. I just need to know where to find the correct wire. Thanx in advance for any help.

 

What year and model, upstream or downstream sensor if any?

 

It is a 94 ext. cab 4x4 CK1500. The wire would be upstream of the sensor. There is wire bundles above the starter against the fire wall. But I can not see any loose wire hanging out anywhere. All I need is a starting point to find the correct wire. The truck runs but will not idle smoothly or maintain a sustained speed in 3rd gear without featering the gas pedal. I know what the problem is, I just don't know where to start. Thanx in advance again!

 

All I can tell you is get a strong flashlight and keep looking back there. It might go into one of the bundles. I doubt it though.

 

I have the same problem. Someone removed the wire on the O2 sensor on my 93. There is no wire to be found. I think what we both need to know is where does the wire originate. I'm assuming it comes directly from the computer, but which terminal? I can't find anything in the Hayne's manual. Any help from any auto electrician would be appreciated.

 

Doesn't anybody know where to find the correct wire harness to trace the o2 sensor wire? Or can anybody point in the right direction to reference the info myself? There has to be at least one of you truck nutz(lol) out there that know the answer to my original question. I really don't want to spend the money to take it to a dealer for a single wire that I can fix if I knew where it was.

 

Well, all I know is that on my 89 truck, my one and only 02 sensor goes into the large wiring harness that comes from the driver side bulkhead connector. It runs along the back of the engine to the passenger side and branches off in all directions once it is in the back of the engine.

I'll look up a wiring diagram for you. What engine do you have, and how many 02 sensors do you have, which one needs fixing, and where are they (Passenger/Driver exhaust manifold, crossover pipe etc).

 

I have a 350 engine. There is only one sensor on the passenger side where the left side cross over connects to the right side. It is a single wire sensor.

 

Well the wiring diagrams I have access to suggest that your truck has a manual transmission, because the diagram for an automatic tranny says that the sensor would be in the Y-Pipe and be heated.

So anyways, your non-heated, left side exhaust manifold sensor has a purple wire that runs directly to pin D7 on the ECM, from what I can tell. There should also be a wire going through the bulkhead that runs into the engine that is about 18 gauge and purple, so my guess is that there's a connector my diagram didn't show me. It looked like it ran right to the ECM from the connector that's on the 02 sensor.

C1 should be your ECM; under the passenger side dash by the blower motor.

(click to enlarge)

Good luck.

 

Thank you very very much for your time looking this up. My description may not have been correct. I thought you call the left side pipe going over to the right was called a crossover. By your description, I guess it would be called the "Y" pipe. That is where my o2 sensor is. Before the converter. I guess this would be a entirely different wire. I am very sorry if I miss led you in the wrong direction. I have an automatic tranny.