Help, my truck won't turn off, among other things

Sounds like your ECU has gone completely mental. I think a lot of that stuff is on the CAN bus, but temp sensor, fuel gauge, and lights are part of separate sub-systems. The common element seems to be the ECU. I had one go bad on an Oldsmobile years ago that kept lying to me about different codes, just random stuff all over the car. All that stuff checked out -- replaced the ECU and all was good. Strange that you have no codes.

 

Yeah, that's my running conclusion as well. Something got blasted up somewhere, it thawed, dropped on something (because, why would you seal fuse boxes/wire harnesses under a truck designed for offroading against.... Extreme carwashes? /S) And has screwed up the ECU. Of course with 70k miles Toyota is gonna make me pay for their design defect ‍. RIP

 

See what Toyota says. Plenty of stories of Toyota providing goodwill repairs after the warranty is over. Not saying they will, but if you get a competent tech who finds a potential engineering flaw and a service manager who fights for you, corporate might be willing to eat some of the repair costs.

 

I'm hopeful for that result, they've not always shafted me in the past, but they didn't do anything about the fact that my truck has been rapidly rusting around the door jams since it was 2 years old because it hasn't perforated yet. Which, colors my experience with this truck (one of 6 toyotas I've had now)

 

Sometimes you just get a bad vehicle. Could be this truck is not destined for you.

Get it fixed best you can, then consider moving on.

 

It's gotta last till I can get an EV taco... I'll wire in manual relays for everything if I have to to keep it going!

 

You’re in Alaska. Can’t you just ride a reindeer to work instead?

 

Reindeer? Gimmie a break, we need much more clearance than those mangey dog sized creatures. We ride 1800lb moose. This is my daughter's steed.

 

Russians ride reindeer, duh.

Alaskans ride bear!

 

LOL. Not sure it's anything you did or stuff getting blasted. The ECU is on the interior - so unless something leaked inside onto it, it may just be a bad part and easy to fix, it happens. If that is the cause, anyway. All that random stuff is just odd.

 

Mouse deterrent device 6 inches of Coyote tail tied to hood support rod NO turds in engine bay I keep tacoma in barn next to feed room

 

Thats a very thin theory, at best. The newer the vehicle the more complex the electrical system is. Just the way it is nowadays with all the safety crap being mandated and all customers yelling about wanting TVs in their dash. 3rd gens are no exception (though better than a lot). An intermittent short or open can be very hard to locate and can present itself in weird ways.

We know the battery that was in there is totally dead. I personally doubt the OEM is much better even though it starts the truck. This seems like the obvious starting place to me. Get a new battery in there, clean the two terminals up good, clean the new posts, tighten it all down. See what happens.

 

And you think you have electrical issues now............

You've put the truck inside in the dry, your blue top puked while on a trickle charger, yet you've not responded to any of the many posts recommending exam of the harness for damage.

 

Have then check battery, alternator, ECU. I had a 2007 Colorado that had multiple electrical and electronic issues but only intermittently. Twice dealer could find no problems, I dug up wiring diagrams and diagnosed it myself and told them to replace the Body Control Module (equivalent to Tacoma ECU). That fixed it.
Electronics can fail.

 

this! KISS!
start with basic diagnosis and cut out the chicken little.

 

That battery is between 6-7 years old, these trucks are notoriously sensitive to any electrical faults.
I would try a brand new battery. DEKA brand is my personal favorite if you can get one.

 

The AGM that died was not dead when this problem started it drained overnight as a result of some device being improperly activated by the electrical controls, the alternator and voltage control module are working fine and providing stable current, your battery theory make sense if these problems were only presenting when the truck was not running. Both batteries hold a stable charge above 12.5V, and there is no corrosion on any of the terminals.

 

Check for water in the padding under the carpet on the driver's side. There are a bunch of plugs behind the kick panel in that area and the padding wicks water up to them.

 

so you did (or had done) measured the parasitic draw? You will have to perform the same test on various circuits with them isolated, to narrow down where the draw is coming from.