Q: my truck when I turn the key I have no power but when I jump it it starts up.

If you have a new, fully charged battery, and the starting system still does not function, there are actually only a relatively limited number of causes. Broadly, either the starter motor/solenoid assembly is faulty or the electrical circuit supplying the motor has a fault. That circuit begins at the battery and includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition switch and terminations. Basically, the starter is either getting power or it isn’t. If the starter motor is getting power but it doesn’t work, the starter is condemned and replaced. Alternatively, if there is no power to the starter, then the circuit is traced until the fault in the circuit is found. Notably, faults can include high resistances, due to corrosion, wire strand breaks, or loose terminals, which can only be diagnosed using a voltage drop test. If you desire that a certified mechanic resolve this promptly, please simply request a no start diagnostic and the responding mechanic will get it diagnosed and repaired for you. Please let us know if you have further concerns or questions as we are always here to help you.