Wiring help needed

[SirDread]

l need some expertise in helping solve my wiring gremlins.

I have errors on the MAF and IAT sensors. Both have signal voltage 5v and the MAF has the supply at 12v but no readings showing up in forscan. I have replaced the IAT and cleaned the MAF still nothing. Now I do have a cut wire on one of the plugs into the PCM but no visible wire that looks like the other end of it. When I checked the diagram I believe it goes to s54 and meets two other wires but what I can't figure out from the diagram is what is S54 ? is it just somewhere 3 wires meet or a fuse as it doesn't have a grounding symbol on it.

Ref - The PCM wiring diagram down the left hand side.
https://fordtransit.org/forum/download/file.php?id=29954&mode=view