o2 sensor help

[lifted_yukon22]

i got under there and looked and theres only the pigtail coming off of the o2 sensor ive looked high and low for the pigtail that plugs into it id like to now were it goes after leaving the o2 sensor so i could track it down.

 

[SunlitComet]

if you look at the picture you will see it is on the harness attached to the left side of transmission.