I agree, sounds like the starter could be the problem. Maybe check for power at the starter wires before pulling the starter, just incase it's the under dash starter relay. Do you hear any clicking or anything when you turn the key to "start"? (you might have to unhook your glowplug relay to eliminate all it's clicking sounds so you can hear the starter relay). If not, 4 pin relay under the dash on the drivers side above the round plug to the left of the ash tray could be the problem - might want to test it. (you take the round plug's mount off to get the relay off, the screws go through and hold a bunch of relays on - I'm sure you'll figure it out).
Only issues with replacing the starter are 1. make sure you put the bolt shims on the new starter exactly as they were on the old one (just be mindful of what you take off and where it came from, as usual). and 2. make sure you put the bracket that goes on the end of the starter furthest from the flywheel back on the way you found it. (2 bolts into engine blot, one smaller one into starter if i remember correctly). If you don't put this bracket back properly, the starter wobbles around and busts it's bolts off after a while.
Good Luck!
P.s. ignition switch is on top of the steering column under the dash. That could be your problem too.
