Rear Diff Lock Anytime Mod 3rd Gen DEVELOPMENT

Didn't read your whole post, as I am getting ready to launch jet-skis. See post 1 of this thread for figure of lock current that I recorded from techstream. You can stop using normal lock circuitry, if put resistor to simulate the lock, which is checked on startup.

 

No worries about reading the whole post. I have been following this thread for a bit but due to school I haven't had time to get involved and help.

Next week I'll have time to dig into this a bit and will post results you're asking for in your first post. One thing is for sure though, if you turn the truck off with the locker "engaged", the locker will try to disengage and the vehicle will not remember that the locker is engaged when you turn the truck back on. The locker switch works just like the ETC button.

 

See earlier in thread, starting with post #1. The FSM shows a half bridge driving the locker actuator and the guys have looked at the signal. Looks like about 77% duty PWM to engage, 50% to hold and drops to zero to let the actuator disengage to its default unlocked. It seems to be measuring current through the actuator to sense position.

Why Toyota does that I dunno. Eaton I don't think does this, just a switch to engage, right? But it's been noted that the Toyota locker isn't exactly the same construction, so it may be necessary to retrofit a higher duty cycle coil if you don't either limit engaged time or use a PWM.

 

To recap, as people are chiming in, and I know this is a long thread.

Lock coil is powered by the ECU, 2 wires
Lock sensor is fed to ECU, grounded when diff is locked
Cockpit lock switch is momentary grounded wire to the ECU, grounded when pressing for lock request

Lock coil is fed with a PWM signal from the ECU to engage and hold lock coil, 2 different signals. Zero voltage applied at any time releases the diff lock. Approximately 77% voltage/current is applied when the ECU is attempting to lock, but detects the diff lock is still unlocked. Approximately 50% is applied when the ECU detects that the diff is locked, to hold in the locked position. To release the lock, the ECU applies 0 volts. (What happens if you apply 12v to the thing, or what happens if you always apply 77% to it, I don't know but I doubt Toyota did it for fun.)

The ECU checks for coil resistance on startup. (so if you bypass the ECU for lock overriding completely, need to put a dummy resistor back in).
The ECU will throw a code if it detects that the diff is locked for too long, and it is not commanding a lock. (So any override needs to disconnect lock position feedback to the ECU when in operation).
The overhead lock request switch is a momentary switch, making it poorly suited for use as a lock-anytime switch for us, unless we include a latching relay in the design.

So, the 'easiest' solution that keeps the Toyota techniques (not 12V applied to the locker...etc) is to remove the ECU from the diff lock coil and diff lock position switch and cockpit diff lock switch. ECU to diff lock coil add a dummy resistor. Replace overhead switch with a normal on-off switch to feed the new circuit. Create new circuit with PWM that when powered, senses diff lock position and applies 77% or 50%, and 0% when off. Feedback from the lock sensor to a new set of lights for lock requested, and locked. So that isn't incredibly hard, but it isn't all that easy either.... and certainly not 'just splice 2 wires...'

I drew up a circuit 'slightly' more complicated than that, but not by much. It only adds 1 additional relay to the above functions to keep the existing lock functions, and just overrides the ECU when you activate the circuit, otherwise the normal locker works as designed. That schematic is in post 77 (https://www.tacomaworld.com/threads...d-gen-development.537810/page-4#post-17382498). I don't think anybody has attempted it yet. And much like 2wheel low mod I designed, I doubt anybody who wants this mod is willing to cut into the harnesses this extensively. I am looking for connectors at this point to see if we can make a plug-and-play version (and include 2wheel low), because I am not going to hack up my truck for this mod, and it wont get tested unless I do it or I make it plug-and-play.

 

Good stuff @BigWhiteTRD and others. Big props for doing all of this. It's more appreciated than you realize. I'm sure I speak for others as well.

 

I had a quick look and couldn't find much for the 10 pin. I have a bit of time tonight though and will check with a couple of suppliers I've used before that always seem to come through on some of those harder to find items.

 

Would it be possible to break directly into the locker wiring and put a switch inline, and completely go around the stock locker switch and dash illumination?

 

This is on the assumption that the 10 pin connector is Toyota part number 90980-10997. I don't have a third gen so can't verify for myself. Here is what I have found.

Female 10 Pin Connector (equivalent to 90980-10997)





Female Terminals (for 10 pin connector)




Male 10 Pin Connector (equivalent to 90980-11102)




Male Terminals (for 10 pin connector)



Or if you want genuine OEM the part numbers I'm coming up with are 90980-10997 for the female connector and 90980-11102 for the male connector. The terminals I could look up the OEM number but expect them to be $10 - $15 each pre-terminated. These are around $0.25 each.

Just a side note that I've used hi-1000 many times and never had an issue. I've linked through Global Rakuten though since the hi-1000 website is in Japanese. The ordering through Rakuten is pretty straightforward but if you need a hand let me know. What you can expect is once you finalize the order they will email you to confirm part numbers and quantities etc. Once confirmed they will ask you how you want it shipped. I usually do EMS which is airfreight. I usually am ordering over $100 worth of stuff which qualifies for free shipping, otherwise I think it is around $15 or so. They likely also have the 20 pin connector and terminals but I didn't check.

If you really wanted to be sure then you could take a look at the connector hooked up to your ECU and compare. The links provide dimensions too so you should be able to get a pretty conclusive confirmation that way.

Hope that helps!

 

Actually if you are looking for a confirmation on at least the female connector part numbers there is a couple of ways. Someone with access to TIS could look them up. Or not many people know this but almost all of the Toyota connectors have the part number cast right into the production molds.



This one for example has “10789” on the connector just above the terminal slots. The actual part number for that connector is 90980-10789. It will almost make you go cross eyed trying to read the tiny print but it is there.

 

Thanks for the help with these.
I will try to put an order together tomorrow. (I will let you know if I need help). I have promised myself to go ahead and build a working proof of concept on this, if no other reason than I want to prove to myself that I designed it right...

 

Okay last post regarding the connectors. Hi 1000 appears to also carry the 40 pin connector. To keep things simple I've linked the two that include terminals with the connectors. I compared dimensions to the earlier TE / AMP 40 pin connector I linked and these are a match. As an added bonus the 40 pin male is not a PCB mount with this option.

40 Pin Female Connector (Including 40 female terminals)




40 Pin Male Connector (Including 40 male terminals)

 

Glad to help. I read through the OP and was impressed with all the work you had put in so far and to be honest would also like to see you finish it off! I bet you if you combined something that could handle the locker anytime and also 2lo mod you would have a very marketable product that people would be interested in.

The 40 pin male connector in the last post would probably be a lot easier to work with compared to the PCB mount... especially if you are just doing a one of / prototype design right now.

 

Ahhhhhh beautiful, now can put the box anywhere. Impressive google-fu skills; I bow before thine glory...
I have a schematic drawn up for both lock anytime and 2wheel low combined in a single enclosure as it is only (1) additional relay. (Probably going to be bulky, with 4pdt relays...)

Would like to replace my hard-wired 2wheel lo, with an easy plug-and-play...

Thanks again for the connector help guys, especially @Up2NoGood & @DaveInDenver , it was a lot of help that I was having trouble with.

 

All connectors ordered I THINK. A little wierd ordering stuff not in English, not knowing what the checkout button, etc.. but if it is a fail then no biggie, I can say I did my best. Thank you again up2nogood. Think everything needed to build (a very inelegant module) is on order. See if I can motivate myself to build it up in a week or two.

This build really needs (in my opinion) a dual color led module, or something similar to give locking and locked indications. Could incorporate flasher, but I just dont like them. Much prefer a light module that would be red for locking commanded, but unlocked. And green for locking commanded, locked... If anybody has a suggestion let me know.

 

I am not a fan of blinking lights either.
I believe the simple red and green tells the driver everything they need to know.

 

Nice... looking forward to seeing your progress and hopefully they are all the correct connectors

If you ordered through Rakuten (the links I posted) you'll probably see a couple of emails first in Japanese, but then one usually within 24 hours in english that is someone from Hi 1000 introducing himself or herself and confirming your order quantities and totals. Once confirmed they will give you some shipping options to choose from and even a final picture of your order.

It's a pretty unusual process compared to what we are used to here in North America where you just place the order and the next day receive a tracking number with no real interactions, but it gets the job done.

 

Yep. I put order in Sunday (us) and they replied this morning... I ordered snail mail...

 

Connectors in
Thanks for the help.
Now to motivate to put it all together...

 

Awesome, have you had a chance to confirm they match up with the connectors in the truck? Hopefully no surprises with that.

 

No, not yet.
Jumping in with both feet on this one. Will find out when try to install it... At a minimum I will just be using the pins to install it, without the connectors. At this moment I am really just trying to justify proving it works to myself...
Thanks again for helping with connectors, I am pretty confident they are right.