Replacing entire frame wiring harness?!?!

Ok, so due to some unforseen consequences of my own stupidity, my exhaust has melted the back half of my frame wiring harness, meaning I need to replace the whole wiring harness or at least everything behind the gas tank.
The frame harness in question seems to run about half of the components in the truck including the fuel pump, fuel system gadgetry, sonar, brake and stop lights, even some abs and tpms I think as I started to get those lights recently.
Long story short, my exhaust got all bent up on a rock and I cut it off thinking it would be ok but heat build up made the wiring harness melt together fairly impressively over the rear axle. I have the new harness on order and have most of the 6 million clips that hold it in place removed but the only spot on the harness I can't get to is just over the gas tank. I'm assuming it somehow connects to the top of the tank but just can't really see it. Am I correct in assuming I'll have to drop the tank to get to that last connector? Has anyone done this whole harness before. It doesn't seem impossible but geez what a pain in the ass.
Also, I started trying to extricate the exhaust behind the clamp at the muffler to replace that chunk. I got the clamp off but the tailpipe is still very well attached, even after a bit of the blow torch and hammer treatment. Seems like it should just fall apart at this point but no dice. Any tips here?
Thanks in advance.

 

There is a thread on swapping out a small gas tank for the larger one. It contains the instructions for dropping the tank.

edit: found it
https://www.tundras.com/threads/07-14-38-gallon-tank-swap-install-thread.27144/

 

I don't know but I thought it was pretty dumb of Toyota to run the main wiring harness so close to the exhaust...Especially the cats. I noticed it while installing some wiring for a backup cam.

 

A good wiring diagram, which are available on this site, shows the locations of all harnesses and connectors.

Depending on how bad it is I might just splice in a new 1 ft long piece of wiring in the damaged area. Get the soldering iron and heat shrink out it would seal up and be good to go.

Or sell me your truck and I will fix it hahah

 

The issue is that it's a few feet at least and there are at least 20 wires. I might trust myself well enough with one but it seems like a recipe for trouble doing that many splices.

 

So I had ordered a new frame wiring harness for the whole back half of the truck and Toyotas parts site said that the part number 82164-0c180 was discontinued but that 82164-0c890 replaced it, but evidently the harnesses aren't exactly the same. The new harness was missing one wire to the fuel tank solenoid and the main ground wire had been relocated in the under hood box as well as having a slightly different connector for the big black power wire to the whole harness. I didn't realize this, however, until after it was pretty much installed as I had left the original mostly in place to ensure I would route the new harness correctly. Perhaps I put too much faith in Toyota but after dissecting the original harness I managed to reinstall the proper wire for the solenoid in the under hood connector and splice in the right connector for the power wire but I'm still not getting it to start, with or without the solenoid connected.
I did get it to almost fire up a few times but it just dies as soon as it starts. I'm suspecting that it might actually be a fuel issue relating to my gas tank somehow as I had to drop the tank and this seems eerily like fuel pump issues I've seen on here and youtube or that there could be some other wire I'm missing that is giving me issue. Mostly I'm curious if anyone.is familiar enough with these harnesses to tell me what it could be (I think this harness was for non flex fuel and I have a flex fuel truck based on the 4 hole gas tank/separate fuel solenoid situation but I'm kinda doubting the solenoid is necessarily the issue as it controls ftp valve and should be pulling a code if that's the problem) I disconnected the fuel line at the intake manifold and it's not squirting fuel even when she does try to start. I double checked all the gas tank connections multiple times and I'm not pulling any codes. I feel like there could be one other wire in the new harness that's off or perhaps my fuel pump is coincidentally dying/some other fuel not getting there issue but I'm not really sure which road to take at this juncture. Any help is very appreciated. This got way out of hand. Ha.

 

First thing I would do is run your vin through the Toyota.com specs and make sure yours is or is not flex fuel.

Seems yes you are not getting power to the fuel pump ecu or the fuel pump.