scotch
+1y
Sounds like the battery has died. Old age? How old is it? If it's only 2 or 3, then maybe something is wrong with it or something is shorting and causing it to die. It was still really weak cranking even while the jumper vehicle was connected?
Do you have a lot of rust on the truck? Check the ground cable on the inner fender near the fuse block. Also check and clean the battery terminals & cables. I've seen some that looked clean but had some corrosion that when cleaned, allowed the truck to start right up.
Check the cables/terminals at eh started too. DISCONNECT THE BATTERY FIRST SO AS NOT TO ACCIDENTALLY SHORT OUT THE POSITIVE CABLE AT/AROUND THE STARTER.