and when you say to connect the red wire to the starter relay do you mean the red wire that was in the last picture i posted coming off of that connector?

 

No the red wire coming off of the fuseable link that is attached to the starter solenoid above in this picture.

And that Fuse link has to be replaced with a new one.

That has to be replaced before we go any further.

You said that your truck has ammeter and oil pressure gauges, and that it moves to the left or toward the "D" side of the gauge with the lights on. This confirms you have a Discharge, and the battery is not being charged.

I believe you fix and replace the fuse link, and red wire in the picture above, your truck will charge again. (If no other problems are present)