1996 4.0l no crank/no fuel/no start

I am new here and not sure if this thread would go here on in the Comanche section because the issue I am having is stock xj wiring but it’s in my mj. (If the thread has to be moved can a mod please move it)

SOME BACKGROUND:
I started with a 2.5 renix Comanche. It caught fire and I went to replace the harness and It was a nightmare tracking down electrical issues. So to get rid of that headache I decided to give myself a different headache.
Sooo, I bought a 96 xj running and driving about a month ago ( 2wd/4.0l/auto). I pulled everything out of my MJ, electrical harnesses, interior, engine.... everything. I swapped it all with the components from the Cherokee. Engine, ecu, body harness, engine harness, steering column, fuel pump/sending unit, dash, gauge cluster, hvac and core support with radiator.
I labeled all the connectors as I was taking it out of the cherokee so I will have an easier time putting it all back together in the mj. So last week I got everything installed and connected. I threw a battery in the mj and to my surprise it didn’t start. I pulled everything from the running and driving Cherokee but now it doesn’t want to do anything in the Comanche.

You turn the key and there is no fuel pump priming, no starter engagement, none of the dash lights come on, and the horn doesn’t even work.

Now I thought my battery didn’t have enough juice so I charged it for about 12 hours threw it back in the mj and still nothing.

I checked time see if the starter was getting power and the big top post was reading less than 5 volts. I changed the cable to a bigger gauge and a newer wire and when it was all connected it still was reading less than 5 volts. I even tried to arc the starter and that didn’t won’t either. I don’t know what is happening but shouldn’t it be in the 12volt range?

Also checked to make sure the relays were getting power and they are. In the process of getting new relays and fuses for the underhood/pass side panel.

Any help is greatly appreciated

I would wonder about your grounding, particularly to the engine block.

The fact that you are getting an odd voltage reading at the starter suggests that something is not making a good connection for that circuit,

You could probably just take a jumper cable and connect it between the negative post of the battery and air conditioning bracket and then check your voltage at the starter. If that brings you up to 12V then work on a proper ground wire and see if you get a functional starter.