Rear Diff Lock Anytime Mod 3rd Gen DEVELOPMENT

Sounds good
Let me know if you have questions, will try to answer. A bit of example

@fuzzydoodle had an elegant resistor installation I thought. (2) 3 ohm resistors in parallel to give 1.5 ohms, used to reduce the voltage into the lock coil. His thread here https://www.tacomaworld.com/threads/factory-locker-install-on-16-sport.692802/

 

Ok I’m almost ready to splice in 3ohm 100w resistor in between red and white on ECU side. Before I do what are the risks? Burn up the 4wd ECU I’m guessing. If this works I will then move to the switch/locker side. Everything will be wired with quick connects at this point.

 

If you attach it between the (2) heavy gauge wires coming from the ECU labelled as SL+ and SL- below, and disconnect those wires from the lock coil, there is essentially zero risk. (They are Black and White at the ECU, or Red and White at the diff). Resistor drawn in red in figure below.

The Red wires and diode are part of the anytime lock wiring.

 

This is red and white going to diff at axle disconnect. Sounds good man thanks!

 

Sounds good
You can also help to verify by checking the resistance between those wires (to the axle side of the connector) with an ohmmeter. Should read 2-5 ohms or so.... (the resistance of the lock coil that you are simulating with a resistor.
I believe that is connector BD1, and you are pulling Pin 3 and Pin 6 (per my memory), so this should help verify as well

 

Did you mention earlier in this thread that all of the splicing can be done in cab at ECU? Because that would be way better.

 

Yes
Plug and play means alot of connections at the ECU.... if you are cutting/splicing, it's pretty easy to access...
But be careful not to cook anything with the resistor (for failsafe conditions)

 

I can't overstate how much I want a plug and play solution to use my locker whenever I want in whatever mode I want. I will pay $$$ for a plug a play solution.

 

Make a WTB thread with a big enough bounty, you will get one (I assume)...

 

I'm in for one!!

 

It's on my list as I said. Lots of folks interested.

 

Damn. You guys working on this are the real MVPs.
Your work/research is very much appreciated!

 

You guy’s are spot on! ECU spoof successful and no heat from resistor. Now on to a new switch. Decided to leave splicing at axle disconnect for ease of access and hopefully never reversal. Everything will get cleaned up later.

 

I’m so pumped about this!!

 

If that works as good as I think it will somebody needs to find the wires in question on the firewall or under the dash so I can pull off the same trick

 

They're already found. In this thread you can find the diagram of the connections at the 4wd ECU. This is the method I started working on but with a microcontroller and pwm output to energize the locker solenoid instead of a high power current limiting resistor.

We also know this works as it's been done more than once.

 

You'll only get heat if you try and lock the differential via the factory switch. If you do that it will treat your resistor as the locker and hammer it with current. Just don't press the stock locker button or better yet, disconnect it. The 3 ohm load now just lets the 4WD ECU's start up check get the feedback it needs from a "simulated locker" to declare everything is normal.

 

At the 4wd ECU (under glovebox), wire 1 and 5, (white and black)

 

Perfect

Now I need to find a place for ANOTHER switch.......trucks starting to look like a damned cockpit