So let me recap this problem.
Then engine will start, push starting the truck.
It will not crank over, turning the key. You have already replaced the clutch interlock switch and the ignition switch?
You need to check for 12volts to the red/ light blue wire [small terminal] during crank at the starter relay near the battery. If none, reply back for further tests.
If you have power there, jump the 2 large terminals with a screwdriver [make sure truck is in neutral] the starter should engage, if it does not, you need to hit starter with a hammer and see if that will make it work, if it does, replace the starter. If it does not measure for 12v getting to the battery cable at the starter.
If the starter works when jumping the large terminals [and had power to the small wire r/bl] Replace the starter relay. Reply back if you still need anymore help..Glenn
If you mean the RAP module, maybe..Need to check the starter lock out relay controlled by the keyless entry module also.
do you have power door locks? if not don't worry about it!
What are the results of the testing I told you to do?