jeep no start wont turn over

The nss switch is new, I cleaned grounds and connections, and I cleaned out the starter motor (brushes were 3/8'' long) bench testing the starter works good and battery is good. I am still having the same problem still, randomly at the worst times the jeep wont start dose not turn over, everything has power and volt gauge is reading 12 volts, when it does happen I can hear a click near the fuse block in the kick panel on the passenger side but that's it. is it possible that the starter motor is not getting power at all? and what would cause this? because it only happens randomly when I am away from my shop it makes it very hard to diagnose. and since I replaced the nss is there a chance that it is not aligned correctly? the reverse lights come on and messing with the shifter doesn't help. when it wont turn over I turn the ignition on and jump positive power from the battery to the small power feed from the starter and that works fine. I really need to get this fixed asap and if its something as simple as a new starter I can replace that but im not certain because bypassing it makes the jeep start up just fine. vehicle is a 2000 jeep Cherokee with aw4 trans

IF you can jump power to the starter solenoid, and it will crank every time you do that, then you need to determine what is stopping the power getting to the solenoid.

Usually, that means ignition switch, starter relay, NSS, or the wiring between all of those.

The NSS simply interrupts the starter relay from passing power to the solenoid unless the shifter is in PARK or NEUTRAL. Yes, if it is not adjusted correctly that will cause interruptions.

I don't know where the starter relay is located on the later models--I would ASS-U-ME it is in the PDC under the hood.

Now, a worn ignition switch--the electrical unit behind the key lock cylinder--can cause the exact problem you are having.

I kind of feel like it could be a worn ignition switch are there any good writes up about how to replace one

I realized today that my jeep has a dealership installed vehicle theft protection chip basically if the chip is removed it cuts power to the starter, its kind of stupid to me. could this be causing my problems and how could I diagnose that?