Electrical Gremlin On My Back! HELP!!

Hello,
Totally new here, first time posting.

2009 Tacoma 4.0 V6 1GRFE 4X4 A/T

Had some rodent damage from engine wiring harness, got tired of splicing wires, found a junk yard harness in great shape where everything was plug n play. The only difference is the "new" harness I bought came out of a 4×2 so it obviously didn't have the transfer case connector or the 4x4 ECU connector so I just left that part of my old harness still on my truck now plugged in and everything else from the "new" harness plugged into all components perfectly including transmission, neutral safety switch, speed sensors, all engine components, etc.

Here's the issue:
[ ] When I turn ignition I get nothing no response from starter at all.

Here's what I've established thus far.
[ ] No check engine light.
[ ] No cruise control light.
[ ] No security light blinking when I remove key.
[ ] Short circuit in dome fuse circuit.
[ ] STA2 Fuse has 12V on start.
[ ] I have 2 ECU's...same response with both
[ ] I have tried #4 #13 pin short on DLC to reset ECU, Immobilizer...same result.
[ ] No power to pin #1 on starter relay, pin #2 is grounded
[ ] All I can think of at the moment.

Apologize for the lengthy post but I'm stumped at this point.


What am I missing?
Any ideas?

 

Welcome..

Hopefully someone like one of these smart people will see this.

@Dm93 @caribe makaira @TnShooter

 

Yes hopefully
Thanks

 

I won't have time to get too in depth until tonight but we can begin with the starting circuit since that's pretty easy to check.
https://www.tacomaworld.com/threads/2nd-gen-information-diagnostics.784008/#post-28042155

Just to be clear which harness(s) did you replace?

I'm assuming you have checked the AM1 and AM2 fuses in the underhood fuse box?

 

Interesting, No CEL at all?
This will either be easy, or we'll be in for a bunch of diag work.

Either way, I'm down. This should be fun.

One question. What year truck did the harness come out of?
And also, did you have to splice in any wires?

 

AM1 has to be good, if the STA fuse has 12v cranking.

One check - Checked

 

See

 

Thanks everyone,
Greatly appreciate
Same year harness 2009
Engine/ECU harness
No wires spliced
Everything was plug n play
No CEL at all at any point...strange

My Fluke meter got left out in the rain by me like a dummy so I'm without a meter for now. Down to just a ol test light unfortunately

 

That will work for most of the checks.

I'd go straight to the Neutral Safety Switch and check the Purple wire for power when cranking. (if you want to start there)
It (purple wire) also goes to the ECM, But for the exact reason? I don't know.

It then goes OUT of the Neutral switch and back into the ECU...again.
Why? No idea. But the ECM needs to see a crank/start signal at 2 places....for some reason.

 

Ok will do.
What does the black/yellow wire do?

 

It's the control wire for the Starter relay. Pin 1 of the relay.
The one you do not have power at.....

 

I’ve done that. It wigged out & wouldn’t work. I put it on my dash with the sun to dry, it works fine now.

 

Copy that going to check purple wire at NSS now.

 

Should be pin 4 (purple wire)

 

Also remember you have to be CRANKING to see power.

 

I think were on the path, but the path won't lead us to the issue. This path will lead us on to a bigger path.
As I feel we have more than a starting circuit issue. I think we have a harness unplugged.

Maybe the 2A or 2B connector in the fuse box......
But we'll see.


Guess where that connector goes?
To the Starter relay, and to the ECU (CEL Light)

 

All I can think is, what a great band name 'The Electric Gremlins' would be.

 

Just because we can, Make sure the connector pictured below is plugged in good.

 

CORRECTION!
UPDATE!

My bad y'all just looked up my invoice from where I bought the harness and it came out of a 2007 4Runner.

Also I my truck is a 2005 4Runner with a 2009 Tacoma motor in it that I swapped out like a year ago but it has ran fine since then before this rodent issue came about leading to this current fiasco.

 

I have the complete factory wiring diagram to 4Runner if anyone needs it to help.