Have 97 Ran Van 2500 5.9 that wont turn over. Replaced ign. switch, starter relay, and starter. Ideas anyone?? Started week ago taking several turns of key to turn over.

 

try the main ground wire from the battery. that wire is always overlooked

 

Also check the wires to the starter for voltage drops. If you can get a Multimeter from the battery + to the starter B+ the you can see if you have a voltage change. More tha .5 volts is real bad. Normally should be <.2 Volts. This would indicate corrosion in the battery cable to the starter and thus a big problem. Same applies to the solenoid power from ignition switch(starter) relay.

 

If it doesn't crank at all look to see if there is a fusible link inline with the starter and the battery.Also you said you changed the ignition switch? Is there power at the small wire on the starter when you turn the key. If not check to see if there is power at the nuetral safety switch when you turn the key.(start position) If there is power there is it coming out of the switch? If it is a standard it will have a clutch safety switch instead of a nuetral safety switch. Keep us posted.