Replacing your engine main room harness?? (Part # 82111-04G80)

Hey guys, new Tacoma owner and new to the forum. I recently picked up a 2013 Double Cab; super clean, with only 39k miles. The only kicker was the rebuilt title, according to the Carfax the driver side fender was introduced to a tree in 2014 and was fixed etc... It's not perfect after looking at the gap between the hood and fender but it's all stuff I can live with.

But back to the main issue, the previous owner said he could never get the key fob/keyless entry to sync, after multiple failed attempts myself I decided to kick it over to my local dealer. After 650 bucks and 4 wasted days, they have determined the main engine harness was poorly repaired and the ignition refuses to recognize a new key. The dealer wanted $7,000 after parts and labor to replace the harness (definitely not happening on my budget).
Fast forward a few days, I now have a new engine bay harness (part # 82111-04G80) in my possession and I'm looking to swap in the new harness. Before I dive in, has anyone does this before? Any tips or tricks would be appreciated! I not I will do a small write up.

 

Wow, Kudos for handling it yourself, love to see.

I haven't done it, but it should'nt be too much of a problem. The top part on the pic is what goes into the cab. Patience when placing the new plugs thru the opening on the firewall. Take pictures before removal and verify new harness to match what the truck has. Plug for plug.

 

Update for everyone: I was able to replace the main harness with only a few issues. I will look to post the write up over the next few days.

My bigger issue is sourcing a replacement driver junction box (inside the cab) part number 82730-04040. Does anyone have one of these laying around and willing to sell?

 

Called TLS this morning and had no luck. Maybe I'll have better luck with lkq

 

https://www.ebay.com/itm/Fuse-Box-E...ash=item36370e5cea:g:PkEAAOSwuINbTOWf&vxp=mtr

 

What happened to it? Does it have physical damage or burnt evidence?

 

I got mine from trdparts.com. I had hell finding a used one. Mine is an 09 and the '11 is the updated one for the 09. The upside to buying new is knowing it will work out of the box

 

There is no physical damage. When I connect the battery terminals, the truck's accessory mode turns on without the key in the ignition. The dealer said they would have replaced it when the write up I was given so I am just following the route at the moment.

 

Seems you might have to add the IGN switch also to parts to remove n replace...

 

Just so we are clear, you're talking about part number 8445071010? It would be an easy fix if I am already in there. Link included below for what I am looking at.

https://parts.toyota.com/p/Toyota__/SWITCH-ASSEMBLY---IGNITION-OR-STARTER/62968515/8445071010.html

 

Unplug the ignition switch and see if the problem continues.

 

If it didn't do that before, my bet, something is just plugged in wrong, check your connections real good, can't hurt, might save so $$$ too.

Tip, just in general, good thing to do on top of taking pics to keep track of plugs on harness swap or engine swap, buy a big set of paint markers of eBay with alot of colors, they like $20. Before you unplug the original connections, mark each side with a matching dot. Then take your old harness, lay it next to the new one, put dots on the new harness to match your old one. Makes it easy to match the plugs on the new harness to the plugs on your truck

On engine swap, when you unplug a plug from your engine, put a dot on the harness wire, a dot on the engine side, once you removed the old engine, put it next to the engine and put matching dots on the new engine

 

Thanks for all of the tips guys. I will try this tomorrow after work.

 

Update: The new internal fuse box (2730-04040) and ignition switched (84450-71010) arrived yesterday. I installed everything last night, triple checked all of my connections in the cabin and engine bay, fuses, battery voltage and still no dice. The truck still powers on as if it was in accessory mode (Radio, AC and dash all turn on) with the key out of the ignition. I even unplugged all connections to the Ignition cylinder and switch and the problems still continues. (truck currently will not start)

Looking at my next options - the dealer had mentioned replacing the ECU after replacing the harness and internal fuse box. I thought this was a little overkill but it seems like we are approaching that road fast. Has anyone installed a new ECU in their truck? Is this something I can do? I am used to working on older vehicles.

Would another option be replacing the ignition cylinder and key? Not knowing the full history of the truck maybe someone mucked up the cylinder from the original repair?

So far I am around 650 bucks for all of the replacement parts

 

You're going to need to follow the schematics and figure out the current flow path to the radio and other things that turn on. I'm on my phone so it's hard to look at the big picture. Here's what I have for you. You can see that the radio is turned on by the 7.5 amp acc fuse. I couldn't find where it's energized from.

Radio schematic
http://www.customtacos.com/tech.old...toyewd/06toypdf/ewd/2006/tacoma/h/em01d44.pdf

Complete schematic
http://www.customtacos.com/tech.old...06toyewd/06toypdf/ewd/2006/tacoma/m/em01d.pdf

Listing of schematics
http://www.customtacos.com/tech.old/files/05FSM/wiring.html

 

Ok, I found the current flow in the complete schematic. Pages 48 through 53 show the acc terminal on the ignition switch. It feeds directly to the 7.5 amp acc fuse and then to the radio.

 

Update and progress: Not sure if i got this right but it definitely looked wrong to me. I decided to remove the stereo/head unit and found that someone had spliced the power from the Engine Immobilizer System plug to the head unit power (white wire pictures below) in an attempt to override the anti-theft system. I simply removed the jumper and respliced back into the appropriate connector. The stereo now remains off when the battery is hooked up to the truck - but the dash remains on and the truck still does not start (assuming anti-theft mode). I am starting to work my way through the main dash harness now.


2nd picture is what caught my eye - the original splice. Id really like to meet whoever thought this was a good idea.

 

So adjust, repair or replace at dealer is a high probability for this stage of repair...

 

Hey Everyone! I am back with some disappointing news. Since Ive last been on, the truck has been at 2 other Toyota dealerships for 2nd opinions. So far I've replaced:

Wiring Harness #1 - Part #82141-04N80 Wire Instrument Pan(New OEM)
Wiring Harness #2 - Part 82111-04G80 Wire Engine Room MA (New OEM)
Ignition Switch Part # 84450-71010 (New OEM)
Cylinder and Key Set Part # 69005-04150 (New OEM)

...but the truck continues to display gauge lights while the key is out of the ignition! I would definitely say I have reduced all of the unknowns within the wiring looms. I guess the next step is to start testing individual components on the steering column.

 

Just to be clear, will the engine start?