My Ford Ranger has power but when I turn It over it won't start?

I can get under the hood and mess with positive wire that runs to the battery and it will start

Replace the wire

Not a vehicle on the planet that is working normally shall do as you describe. Electrical issues are well known to cause major damage to the sensitive electronics of vehicles. You failed to identify the year of the car or its general condition. It is my best advise that you take this vehicle to a trained, certified and experienced mechanic before there's major damage to the Ranger. In the photo a 1931 Cadillac on exhibit at car show. It is better than new for it has been cared for since it was sold. It is 83 years old. Will your Ranger be with you when you get to be 83 years of age? It can be. Please go to a mechanic for a simple repair before something worse happens. Electrical issues are serious ones. Do no delay. Lastly, if you read both responses you have received so far you shall see that all sentences end with a proper punctuation mark. Why did you not place a period at the end of the second sentence? It is your teen "rule" to follow the grammatical errors of other teens? Not advisable. Please punctuate All sentences. ALL. Please edit and correct.My Ford Ranger has power but when I turn It over it won t start

Check to see if the lead is frayed or damaged, if not try tightening the wire to the battery terminal. Another thing you can do is run a multimeter from your battery terminal its destination to test for voltage drop across the circuit. If the voltage at the end of the wire is different to what it is at the battery terminal, that lead is damaged and will need to be replaced.

Hope this helps.