Check the connectors to the batterys , load test the batterys , do the check to see if there is power at the starter , both the large cable-batt. + and small wire at solinoid-thats the wire that turns on the starter with the key in the start pos. , once you've check all these , and all that checks out then , this is best down with a remote starter sw. but can do with a short pice of wire , turn the ing. sw. to on and jump the small wire from ing. sw. to the cable [ both on the starter & solinoid ] and that should start or turn over the truck , and elimit everything els , and if that doesn't work than its the starter & or solinoid , if it does work by jumping and not by key then look at nutrual safty sw. and other stuff.