Rear Diff Lock Anytime Mod 3rd Gen DEVELOPMENT

Simply holding the traction control down for 3 seconds disables the Trac/ abs doesn't it??

 

Disables TRAC and VSC. Doesn't disable ABS. But I hate to count on somebody doing that.

 

Working on schematic design now, but I am up against a bit of a wall, and need input. Please anybody give input if you think you are likely to do a 3rd gen anytime locker mod. (I made my 2Wheel Low design such that button activation should never cause a damaging event. It doesn't look like this mod will be the same. Looks like improper use of this mod will probably damage the diff.) I am a bit concerned about activating inadvertently but that may not be a big deal for the users of the mod

What is the consensus, on how we should operate anytime lock? I can't decide which is best yet.
Here are some options I have considered

1. Use an added switch, keep normal switch and circuitry for in 4Lo, use added circuitry on added switch only. Makes electrical design simpler, but adds additional switch that must be located someplace. Added switch has essentially no protection against activation when you shouldn't activate. Still gives backup normal operation if added circuitry fails. New switch could maybe be guarded, or perhaps press and hold to activate to make inadvertent dangerous activation more difficult.
2. Use existing switch, completely replacing normal circuitry and operation. Makes electrical design easiest, but doesn't give any normal operation backup should the new circuit fail. Do not include any protection from inadvertent operation. Does not include any protection from hitting the button at any time.
3. Use existing switch, completely replacing normal circuitry and operation. Makes electrical design easier, but doesn't give any normal operation backup should the new circuit fail. Try to include some kinds of protection from hitting the button inadvertently and damaging the diff. Possibilities I have considered are double operation like operate a switch and hit a button, or have to press and hold the button, etc.
   
4. Use existing switch, new circuitry in 4hi and 2hi, but use existing circuitry for 2Lo. Much more difficult to create the circuits for. (Thinking of using an arduino microcontroller due to complexity.) Do not include any extra protection against inadvertent operation.
5. Use existing switch, new circuitry in 4hi and 2hi, but use existing circuitry for 2Lo. The most difficult to create the circuits for. (Thinking of using an arduino microcontroller due to complexity.) Try to include some kind of extra protection against inadvertent operation.

Thoughts and suggestions about how we make this thing operate?

 

Option 1

 

I agree for option 1 as well

 

I appreciate you I was admittedly excited about the possibility of locker anytime so I forgot to thank you for your work on the 2lo project.

 

I'm down in Stuart if you need a local test dummy.

 

I hate to sound so stupid, but why couldn't we

All you need is a disclaimer, post that shit! I loved the option on my 2nd gen. It's the users responsibility what they do to their vehicles. Any possible issues being noted are helpful as to whether or not someone chooses to do the mod though. I'm down!

 

Hate to ask the obvious, but have we tried simply tricking the shift location switch (that tells computer if it's actually in 2H 4H 4L) into thinking the truck is in 4L, but otherwise deactivating the shifting mechanism so the truck stays in 2H? That might be the most elegant integration yet.

That said, I am voting for Option 1.

 

In attempting to trick the ECUs, how do you plan on addressing the wheel speed sensor failsafe?

 

Do we know that is a problem? I don't know what it would do...

 

The consensus is definitely option 1, and I am drawing now. Note, the Rev 0.1 of the schematic is going to need refining and adjustment, because we need to get PWM values locked down. If all goes well I will have a rev 0.1 schematic and will order the parts to bench test tonight/tomorrow. (now I am promising like OVtune...) And yes, I know people aren't waiting for this with baited breath like they do Matt.

 

I played a little with tricking the 4wd sensors (on the transfer case and front diff) when working on 2wd Lo mod. If you do 2whl Lo mod you can use rear diff lock in 2wd low, just not 4hi or 2hi.

But what I learned is that the ECU is very good at spotting unexpected things. You could almost definitely do a locker anytime mod by tricking the feedback 4wd sensors and switch it into 4wd dash dial, but it will still prevent SWITCHING above 5mph.

Based on my 2wl Lo mod I think it will be quite hard, and alot of wires to cut. (2whl Low required a 4pdt relay) just to trick the front ADD. If I could come up with a connector for the ECU to allow a plug-and-play harness it wouldn't suck so bad.

The ECU is just programmed with so many failsafes and checks it's crazy.

 

Circuit I intend doesn't trick the ECU (I have given up on that, especially after dealing with it on 2whl Low mod, but others are free to keep working on it), instead it disconnects the ECU from the rear lock coil and creates an equivalent signal to the lock coil. So if the ECU gets pissed off it won't be able to unlock the rear diff, because it didn't lock it. From the failsafe charts I reviewed and my experiments, failures generally just lock 4wd mode changes until power cycling the engine. In fact, I intend to draw the schematic with disconnection of power to Pin 46 to Skid Control ECU Master Relay Connector S1. This appears on my truck to kill ABS, VSC, and 4WD mode changes.
So if you follow my intended schematic, you can use the anytime lock in 2hi and 4hi, at any speed, but it will disable 4wd mode changes once you activate it, and you have to deactivate to switch modes. Nobody doing the mod has to do this, but that is my plan for the schematic.
I haven't found a good way to disable ABS and VSC without killing 4wd mode changes.

This is what I wrote in 2Whl Lo mod, and still think it is applicable. "So in actual developing this mod (2wl Lo), it makes you understand just how 'delicate' the 4wd system. 'Delicate' not that it is necessarily easily broken, more that the computer is programmed to monitor so many variables and when any unexpected signals are detected from the sensors, the system goes to fail-safe mode. In this particular system (from anecdotal evidence), that usually means the mode changes are cancelled and you are locked into the current mode. I am sure that for 99% of the users and 99% of the time this is exactly the best course of action to protect the truck from any further damage to itself." But for modding it sucks.

 

Edit Removed Poll
Results as follows. Schematic Rev 0.1 leaves original switch. Any (inadvertent operation) protections on the added anytime lock switch will be at the installer's discretion and responsibility.

How would you want to activate Anytime Lock?

1. New Additional Switch (separate from the original locker switch, original switch still works in 4Lo)
   8 vote(s) 47.1%
2. Original Switch (replace original circuitry with new anytime circuits. No inadvertent protection)
   1 vote(s) 5.9%
3. Original Switch (replace original circuits, add some inadvertent protection like press and hold)
   3 vote(s)17.6%
4. Original Switch (keep original circuits in 4Lo, new circuits in 2hi and 4hi. No inadvertent protect)
   0 vote(s) 0.0%
5. Original Switch (keep orig circuits 4Lo, new circuit for 2hi & 4hi. Add some inadvertent protection)
   5 vote(s) 29.4%

​

 

Rev 0.1 of my preliminary schematic. PRELIMINARY. PRELIMINARY
If you somehow make this work, it will lock your rear locker at any time, regardless if it is a BAD idea. This bypasses nearly all of the protections Toyota included on the locker, and you will be able to destroy your diff.

Note:
This schematic is based around an off-the-shelf PWM motor controller, with a resistor network to set it to unlocked (hi power) and locked (low power) setting. The values of the resistors HAS NOT been established. Potentiometers may be used in place of the resistors, and that is what I will do until locking the values down. (Its possible we don't need to set the locker to high power and lower power states (eaton electric lockers don't), but Toyota does so I have drawn it that way.)

It has a single NEW added Lock Anytime switch that is to be added to the truck someplace (possibly guarded or otherwise protected from accidental operation). The schematic is drawn with two lights to be added in proximity to the switch, one for 'lock switch is on but the diff hasn't locked yet', and one for 'diff is locked'. These could be a single red/green LED, or include flashers, etc. As drawn, the locked light shuts off when you turn off 'anytime lock' even if the lock is still bound up locked. We may want to change the way that works. However the dash light should still work in that case I think...

This is a PRELIMINARY DESIGN electro-mechanical type, I will not guarantee anything about it yet.

This circuit disconnects the normal lock lights and lock controller when active. It then sends the lock power to the coil using a PWM motor controller, controlled by feedback from the lock sensor to operate new warning lights and select high power and low power on the controller. The dash lights are disconnected from the rear locker when this is active, so diff lock won't show on the dash. If you wire the power cut to pin 46 of the skid control ecu, then ABS, VSC, and 4Wd mode changes are unavailable when locker is turned on. WARNING, these come back on when you shut off anytime lock, but it can take a minute for the lock to disconnect. DO not have the anytime lock active when powering up the truck, it will notice the resistance error and cause a fault, requiring a truck power cycle to clear.

Preliminary parts list

DPDT Relay for setting PWM to high or low, and controlling added lock lights.

$10 uxcell IEC255 DC 12V Coil 8Pin DPDT Electromagnetic Power Relay w Socket Base

https://www.amazon.com/Uxcell-a15062300ux0219-IEC255-Electromagnetic-Socket/dp/B017LB4AZ6/

4PDT Relay for disconnecting the normal lock controller and lock signals.

$14 uxcell 35mm DIN Rail DC 12V Coil 4PDT 14P LY4NJ General Purpose Power Relay with Base, Black

https://www.amazon.com/gp/product/B00EZ1JUXS/

PWM Motor Controller

$10 RioRand Upgraded 6V-90V 15A DC Motor PWM Speed Controller 1PC

https://www.amazon.com/gp/product/B00F839VNQ/

Also need
Some low current large resistors, or large potentiometers will be required, probably in 1Mohm to 10Mohm range (just guessing at this point, don't know yet for sure)
Diode, to provide flyback protection on the lock coil
A bunch of wire, mainly 20 awg or so but some 18 or 16 awg would be recommended for the larger power wires. I always recommend M22759/X wire (really any of the types are so much better than the crap you get at autoparts places, but I usually use what I have on hand /18 or /16 type wire.) Numbering is Mil-w-M22759 or SAE M22759. The wire type and size are given by 22759/Wiretype-Wire gauge, such as M22759/18-20
A bunch of connectors to attach to relays
A bunch of connectors to attach to the existing truck harness or maybe T-taps (I HATE THEM)
A switch for 'Anytime Lock'
Lights to show current lock status
Maybe a fuse or two, haven't drawn any in yet.

OK, throw rocks
And I don't recommend anybody start trying to modify their truck yet.

 

That right there as far as wiring goes is beyond my current understanding. I remember some of the basics from when I was in Engineering, but too long ago forgot so much.

Thanks BigWhiteTRD for all the work you are putting in to this even though you probably won’t use it as you said be for.

 

If you are willing to be a guinea pig installation, that might be a possibility. Not for a few weeks minimum though.

 

It looks daunting, but I or somebody else can build 90% of that up on the bench. The question then is you (and others) be willing to open up your dash and locate the 4wd ECU. Then cut about 4 wires on the 4wd ECU harness, and connect to the new anytime wiring bundle, connect power and ground, and install a switch...