Troubleshooting a p0113 error in my truck "iat high value - reads as -40℃"

Iat connector shows no +5vdc voltage across and about 150k ohms to ground in red/gray wire.

Cabled as grey (from Pcm to iat) and grey/red (back to pcm after it goes through o2 sensors, dpfe, and speed sensor)

Which of those two is supposed to be the +5vdc supply, and which is the control/signaling?

I hooked a fox and hound up to the grey wire and traced it to this big electrical junction but not out the other side. (Pic with red circle below)



I unwrapped some of the cable shroud and it didn't look like its been replaced since those are factory colors. (Pic below green circle)




Here is a circuit diagram for the iat: (outlined in red)



Any help would be super appreciated.
Does this large block connect to the pcm? I couldnt detect the gray wire signal on the other side. Is this where my break is?