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 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

 

likely to be bad earth, or bad main wires...the big wires that go from the battery supply the alternator, starter, and PDC...you should have 12V strong enough to light a headlight from any of those points

check your earths

perform a voltage drop test as per Youtube

 

How would I check my earths. Those are my grounds correct?

will look up that test

 

There are many posts on here, that include a picture of all the earth locations, check Archives

This is what I would do next...wire up a headlight globe as a test light..put the + wire on the test points I mentioned

Put the - (earth) probe on alternately, the battery negative, chassis, and engine

It should shine brightly every time

If not, the flow of electrons is interupted by something

a multimeter is no good for this test..it must pull high amps __

 

Figured it out. Was bad grounds. We are all good now