So I'm stuck with a torn apart jeep and I'm not sure what to do next. Here's the story so far.

1990 cherokee Laredo recently lost my rear running lights. My dash lights had gone out a month or two prior but I was ok with that.
so far I've done this,
I started to check the rear end lights which to my knowledge all worked still, but I planned to replace them all but they are all so stuck and glued in I literally had to tear out the metal base bit by bit to to remove the 2 I tried to get out that broke when I pulled. So instead I disconnected the harnesses for both sides and removed them completely. I also removed my head unit completely from the dash as well as the driver door speaker that cut out a couple times a week ago till I kicked it. I unhooked all harnesses on the hatch that went to the rear wiper and defroster and other things.
The two dash panels are off and I even replaced the headlight switch to make sure it wasn't the issue.

when the plunger is pulled out one click the fuse blows. Right now I have a license plate light bulb in place of a fuse to save fuses. It lights up bright when I pull the plunger.
when it's pulled all the way out to turn on the headlights they turn on no problem.
I visually inspected the towing harness and followed the wires as far as I could see in the hole where the rear driver side light fixture goes and didn't see anything. I didn't see a harness in there either to disconnect the wires going to the tow harness. I've visually inspected the wires under the dash and resurfaced the ground wire that's mounted on the metal bracket down there. I guess im supposed to check the wires further and see if one is grounding somewhere but i don't know where to begin exposing them as they dissapear into the body.
would a bad bulb on the instrument panel cause this?
I bought a multimeter but I'm not sure how to use it for this situation to aid me.

does disconnecting all those harnesses tell me that those things are not the problem?

any guidance would be amazing. I'm hoping I can figure it out in time to go steelheading but it doesn't look good.
I suck at electrical

 

Well I the worst best case scenario happened. It's fixed but I don't know why lol. I'm now going to start putting it back together one harness at a time and check each time to see if it blows again. I'll update if I figure anything out

 

So there was one small harness I missed on the hatch behind some other wires that was the culprit. It has two wires going into it. One is blue and the other is grey.