Cooling fan runs intermittently after engine is shut off

I was looking at your wiring diagram for the radiator fan. If you pull that 50 amp fuse when your through with the vehicle for the day, if should kill the fan, so it won't run the battery down. Then plug the fuse back in when you drive it.

Note the two fuses in diagram, the one that says heater is voltage for the coil side of fan relay. As the text says, that fuse circuit is not hot, unless the key is on. So with key off, that circuit is not hot, and the relay won't energize, the fan won't run. With key off, check that circuit for voltage, use a test light to check for voltage. If it is hot, either something wrong with ignition switch or that circuit is shorted to voltage somewhere. Hopefully the relay is ok?

I suppose there could be other issues, but, with the key off, I don't see it.