Need Help! 02 sensor issues/Identifying some plugs

[bbrody913]

Wassup y'all I have the 02 sensor code on my truck code 45 89 GMC c1500 4.3L went to the auto parts store and got a Bosch replacement went to change it and the sensors are diff the one on the truck looks to have a female nut any ideas? Also I was going over everything under the hood and seen 3 plugs that where not plugged in anybody know what they could be? All help appreciated

 

[Schurkey]

WHERE is the O2 sensor? Looks like someone moved it from the exhaust manifold then welded it directly to an exhaust pipe. Hopefully, that's not the case. Looks bad.

First wire end looks like for some non-computer accessory. Under-hood light comes to mind.

Second wire reminds me of the one for the AIR solenoid.

Third is totally unrecognizeable. No idea.

Does this truck have headers? Might explain the O2 disaster, and removal of the AIR system.

 

[bbrody913]

WHERE is the O2 sensor? Looks like someone moved it from the exhaust manifold then welded it directly to an exhaust pipe. Hopefully, that's not the case. Looks bad.

First wire end looks like for some non-computer accessory. Under-hood light comes to mind.

Second wire reminds me of the one for the AIR solenoid.

Third is totally unrecognizeable. No idea.

Does this truck have headers? Might explain the O2 disaster, and removal of the AIR system.

The 02 is on the passenger side right after where exhaust connects to header looks to be in factory spot and they are factory headers. Other plugs don't seem to affect anything so screw it found out the last plug the burnt up one is for coolant temp sensor appreciate the input bro

 

[GoToGuy]

Did you try looking the service manual. Has engine drawings with locations and ID of all wires and sensors. What the connector looks like. All ya gotta do is look at the locations and it's either plugged in or missing. If it's missing the drawings tell you which one goes where. Couldn't be any easier.
Download the free your year service manual. Section eight, answer all your electrical questions. With photos, locations, even tells you the wire color! Good luck.