Junction box problem! HELP! I HAVE TO HOLD THIS PLUG IN TO CRANK AND TRUCK WORKS FINE! CRANKS AND LET PRESSURE OFF AND DIES

Typically when you have to put sideways pressure on a connector for it to work, there's three things to look for. The most common is a stretched or corroded terminal. Most of the time you can slide a pick in beside the terminal to squeeze it to make tighter contact. If it's corroded, you'll need to disassemble the plug, then release a little plastic finger to allow the terminal to be removed, then you can replace it. GM and Chrysler dealers have replacement terminals available. Ford is well-known to not make repair parts available after just a few years so the best alternative is to visit a salvage yard to get a terminal out of a plug. If you have to pick it to make it fit tighter but the plug design prevents you from doing that, you'll have to pull the terminal out, then squeeze it gently with a needle-nose pliers.

The second thing to suspect when you're working with a connector that plugs into a computer or anything with a circuit board is a terminal that is broken loose from the board. To fix that you have to get the board out of the housing, and remove any protective jelly, if that is used, then resolder the terminal to the board. TV repairmen ran into this every day once tvs started to be made with automated assembly techniques.

A less-common problem is a break in the wire just outside of where it is crimped to the terminal. Sometimes a clue presents itself where the wire's insulation is slightly discolored right next to the terminal. To verify that, hold the plug while you tug gently on the wire. If the wire is broken inside the insulation, that insulation will stretch like a stiff rubber band.

Please use punctuation so I read what you meant. I suspect the battery is not the issue here, but I'm also concerned there may be some modifications that will void any warranty. Some dealers can get rather snotty about that because if it turns out the manufacturer can figure out something was done that affects the warranty, they will bounce warranty claims and the dealer will be on the hook for the bills.

My suspicion is the symptoms changed due to tugging on the battery cables or repositioning them. That doesn't really fix anything. It just masks the problem, then it will show up later. I would stick the original battery back in, and undo any other modifications, then let the dealer worry about the intermittent problem. You can show them where you were working that affected the problem, but leave it to them to diagnose it after that.