C15 Acert Melting Wires and IVA stuck

Yes as far as I know. The master tech at cat shop did the work and have triple checked it. Everything was torque striped

 

Also the check engine light doesn’t work. Even when it logs codes their is no light. It works on the screen when you first turn the key on when it cycles through all the lights. But to get the codes or even check it we have to hook the computer to it. Anyone have any ideas for that as well?

 

Cat says it’s heat related but I think it’s electrical because the wire burns from the inside out. One of the times the wire coating looked new but the wires on the inside were fried and broken in half right at the black connector where it bolts to injector

 

What is the rack?
And theirs no soot anywhere I can see. It’s a factory motor, no tuner, with 8 in straight pipes