Central Locking and Keyless Entry Quit Working ¡SOLVED! BCM Location & Wiring Diagram

TLDR, I fixed it and if you're here for the BCM info it's below this post!

I'll keep this as short as I can, but I've already spent an entire day trying to solve this so there's a lot to say. First off, I KNOW IT IS MY FAULT so I would really appreciate it if the comments were more constructive than critical.

My truck, 2013 4.0 4x4 6MT Access Cab, had one of those second-hand-dealer-installed "security" devices spliced into my harness that has started giving me trouble. Not locking sometimes, alarm going off 10 seconds after I open the door, and other annoying stuff I could live with until it cut power to the ignition in traffic. I looked up online about them and found a video of a guy removing an identical device to mine from an FJ so after watching it I thought it looked pretty easy and decided to go for it.

I did not disconnect the battery because I thought I heard something about having to reset the immobilizer, which I have since learned is not the case. I figured it would be okay since I was just removing stuff and the only wire I needed to solder was a key'd 12v but I have never used these stupid scotch locks before and one of them I was trying to take off came apart and the blade, still stuck in the wire, shorted out to something when it flew out of my hands. The door locks freaked out for only a second or two until I could get the wire back but that was apparently all the time it needed to get ruined. I know I deserve to be fun of but I just want to fix my truck and I need your help, please.

I need help finding a wiring diagram of how the central locking system works because I have no idea what I fried. Everything seems to work except for the doors actually locking or unlocking automatically.

What I know:

1. When I hit the lock or unlock button inside the truck, I hear a relay clicking under the dashboard near the steering column.
2. The door actuators work. I removed the door panels and when I put 12v straight to the pins for the motor locks and when I flip them the other way it unlocks.
3. When I hit lock or unlock on the remote any number of things happen depending on how the locks are positioned at the time:
   1. If both doors are already locked:
      1. Press lock and get the single Toyota beepy-chime-not-the-horn noise, relays, and parking lights flash.
      2. Press unlock once and BOTH doors try meekly to unlock but fail and there is no double chime.
      3. A double press results in the first one attempting to unlock both as stated above while the second press has no effect and neither press chimes or flashes lights.
      4. Repeated presses result in nothing unless I wait a few seconds and try another "first" press.
      5. After I have hit unlock any number of times if EITHER door is manually* unlocked it gives the double chime and flashes lights.
   2. If both doors are unlocked:
      1. Press lock and hear relays but get no movement on the actuators, no chime, and no lights.
      2. Press unlock and hear relays, weak movement on the actuators, two chimes, and flashing lights.
      3. If either door is manually* locked it does not change behavior.
   3. If one door is locked and the other is open:
      1. It behaves exactly the same as if both doors are unlocked.
      2. Pressing lock and manually* locking the unlocked door will get a single chime, relays, and parking lights flash.
4. Using the key outside the door at any time attempts to unlock both doors on the first twist and nothing on the second twist. It does not try to lock the passenger door at all.

* Manual actuation via key in the outer lock cylinder or flipping the lever while sitting inside. must be done simultaneously with remote press to achieve results.

 

Check these fuses with a multimeter or a test light. Do not trust a visual only check.

IG1 NO2 Fuse
Dr Lck Fuse
and ECU-B Fuse

This function is controlled by the Body ECU which is on the rear of the interior fuse panel.

 

I didn't see an ECU-B fuse, and I actually unbolted and looked behind the fuse box already and didn't see anything that looked like an attachment to the back of the fuse block. No sticker or part number other than the TMB-37. What exactly does this BCM look like? I'll go back and double check the fuses but the relays still work and the actuators try sometimes so something is getting power.

 

On the rear of the interior fuse panel, the ECU-B is inside the panel cover.

 

THANK YOU, SIR! I have not been able to find anything this helpful in days! I have a replacement junction box coming from a wrecking yard this week and hopefully this is still inside it because at this point I strongly believe the problem lies in the logic circuit.

Your lovely diagram idtenifies the three blue relays in the back as being for other systems, where are the relays for the doors that I'm hearing?

 

As you can see the door locks are controlled by the Body ECU Board itself, there doesn't appear to be separate relays involved.

 

Spectacular diagrams, thank you! That is what I've been looking for this whole time! I'll have to assume the relay is integral to the BCM then because, as crazy as this project is making me go, I don't think I'm to the point of hearing things yet.

 

SOLVED!

I got my ebay replacement junction box (TMB-37) in the mail and dug into my dashboard to replace my damaged BCM. I decided I had little to loose disassembling the old one and discovered that the damage was simply a burnt trace and after soldering a jumper in place over it my door locks worked again!

I didn't think to take pictures while I was working because I was racing the sun going down, but now that I'm finished I took apart the replacement junction box/BCM for a few photos to share.

First is the back side of the JB with the cover removed from the BCM, in case anyone was as confused as I was trying to find it and everything saying "it's behind the fuse block"

Second I've circled the trace that was burnt in my original module and identified the corresponding pin on the internal header. Short of checking continuity on every pin on the JB I can't identify where it goes from here as the beautiful schematics from JimmyH only show the outside connections, implying Toyota probably didn't want people taking these things apart

I was relieved to find those three 1A relays on the BCM board because I was beginning to question my sanity! Thank you again for you assistance. I used those diagrams to determine that everything outside the box was good before I dove in to buy a new one.

All that to say, if anyone needs a TMB-37 or a BCM from it lemme know!

 

Pretty sure this fuse box is not compatible with a 2006 is it. I need a fuse box as well.

 

This looks suspect as well (circled in blue).

 

A couple of questions. Is a TMB-37 from one year compatible with one from another year? I have a 2011 that needs a new BCM and can find plenty of 2010's. Did you have to reprogram your keys for the new BCM?