I drove my truck and after it sat for a week it now wont start. With the key in the run position, I have voltage to the coil. When I turn the key to the start position, the starter turns over but I no longer have voltage to the coil. It seems I have a short in the system somewhere. Can anyone help?

 

Don`t know but possibily bad ignition switch or dirty/loose plug connection to it. The ignition switch is bolted to the steering column under the dash.
Also check that the battery connections are clean and tight and that the ground wire from battery to engine is in good condition and connections are good.