OK, I think I understand WHY now.
The wrong battery is in there. The positive (+) post needs to be towards the center of the truck, but it should be to the REAR of the truck, not the front. Your battery cable is too short (I don't see the cable going to the starter)
Then you can get rid of...
So, when you turn the key to RUN, is the CEL illuminated?
If not, then there is something not allowing the ECU to be in a ready state. Assuming, of course, that the bulb in the CEL is good.
Check the fusible links and ALL of the fuses under hood as well as inside the cabin. Make sure to...