Doesn't happen all the time only after it sits overnight or a long period of time during the day.
Turn the key and will not crank over... Doesn't happen all the time. on 2003 Chevrolet Express 2500
This could be as simple as a bad connection or a starter you need to check power to the starter terminal while no start is occuring and ignition is in the crank position if there is power its a bad starter if there is no power it could be a neutral safety switch or ignition switch
AGREE WITH #1 SEEK DIAG AS NOT TO WASTE MONEY