E LOCKER FOR 3rd gen?

If you already have a manual transmission in a 2016-2020 6MT Tacoma, swapping in the factory e-locker is probably the easiest swap mechanically - you just buy the whole assembly and bolt it in. That said, electronically it's not as straight forward, but still not awful.

The rear e-locker from Toyota is about $1850, the control module can be had for about $260, and the switch goes for $60. Add in some connectors and wiring supplies and you're probably around $2300 to add the locker to a manual transmission truck. Not as cheap as an ARB, but only about $900'ish more I figure (give or take).

Jeff

 

I won't have the stock control or anything, mine is a sport. But I wanted a re gear, its got no stop light power, and is awful shifting on the free way. I looked into a few shops in my area about re gearing and 4.88 were the popular option, for me that seemed too much for what i needed. I caught a wrecked offroad manual and figured a bigger rear end and 4.30 gears would be a little extra power but not too low for the few times I go offroad, to get the best middle ground.

The overhead control was in the cab, but thats it, the axles front and rear, but the rear axle has an extra pigtail, so it has the abs sensors, the locker and one more, that doesn't look present on my truck so I'm not sure if I could just plug the rear axle up in there and connect the overhead (with the stock diff lock button). I assume the wiring would largely be the same truck to truck minus the options.

I was thinking of grabbing an aftermarket stock style switch for the rear diff lock (like this https://www.ebay.com/itm/254623299217 ), and just wiring that to a relay, to the locker. The two of you are far superior to my knowledge, I read through your post and it was Greek, like most red blooded Americans i despise wiring, mostly because we're not smart enough.

But thank you both immensely for your knowledge, if youre willing the info may help someone in the future, but you'll have to be patient with me, you guys might as well be talking Chinese to me.

 

Here's the truck's stock control that I mentioned. This is a log going from the unlocked state to the locked state. In the blue trace you see when the lock was requested by pressing the switch. In the yellow trace you can see when the diff actually became locked via sensed position from the indicator switch in the diff. The red trace is the actual current the lock solenoid received. After the diff lock request occurred and while it was trying to reach the engaged state the solenoid received 3.5A. Once the diff lock was actually engaged the control currents drops to 2A just to hold it in the engaged state.

We know the resistance of the solenoid is about 3Ω so that means when boosting the diff lock into the engaged state there's about 10.5V across the solenoid and once engaged there's about 6V across the solenoid. This would equate to pwm duty cycles of about 75% and 43% respectively if using the raw 14V from the electrical system. And you can work out the resistors if you want to do it with a voltage divider just make sure the resistor can handle the power you're asking it to dissipate.

 

Just to reiterate similar results, here was my plots from testing back in 2018.




Things I found interesting in the past:
When the diff is unlocked, the ECU targets ~16 amps (which is not feasible at 14v), but the ECU only provides 75% duty cycle at that time. That is the reason that I dont recommend exceeding approximately ~10.5v. That said, the coil may be good for the 14V, but I havent found any proof of that yet. Power dissipated in the coil is nearly double at 14v as at 10.5v, because P=V^2*R

 

P = V²/R, but yes, nearly double the power. I'll make sure to note next time where something made me figure the solenoid is well shy of its max rating and then share it when I do.

 

So let me get this straight, in layman terms, the solenoid (or locker), doesn't utilize, or need the whole running voltage of 14v.

So these graphs illustrate that the system does a whole bunch of things that my teeny brain doesn't comprehend, with a whole bunch of jargon to explain it that I dont get.

What I'm scrapping off the top here, is grab a switch, wire that sucker up with a couple resistors to drop the voltage to 7-10v.

I guess to me, it seems a lot more simple than you guys trying to unlock and lock when the vehicle system hasn't hit the parameters it needs, like being stopped, or 4lo, or whatever. Where as I'm just powering it to lock when I push a switch, kind of like a light bulb, its on, or its off. ‍

 

That's basically correct. Get some voltage 10 or below to the locker. But remember you're carrying some current and powering an inductor so a relay and a flyback diode would be part of the bare minimum power circuit suggested.

 

As @ShimStack alluded, if you do use a resistor to drop the voltage to the coil (and we are not 100% sure its needed, but it should be safe to do so), it requires a serious resistor and heat sink. The rest of the parts are not crazy, just typical latching switch, relay, and a reasonable diode (for flyback or snubbing).

A second part, though, is do you want any indication of locked status of the diff lock? A locked light, etc? (but dont expect to make any existing dash lights work for that). Only true if you are using the OR/PRO rear end with the lock switch installed.

 

It is the off road read end, and I do have the lock switch from the overhead console, but I dont have the body control module, which i assume would be what controls that stuff, or even the wiring on the truck side to receive the axle plugs.

That was my hope originally, thinking they have to have the same wiring harness, so it should be pretty relatively plug and play...nope.

So we're just going to have to try a different way. The switch I was looking at is like the switch I have for lights, it illuminates when it's on, not ideal, but it'll work.

The thought was, eventually, I'll get the front diff needle bearings replaced, and east coast gear does front e lockers, so, that has to be wired up somehow, this one should be the same....ish.

 

The wiring may not be there, but you'd still be able to do it. Get the correct module from a TRDOR or Pro, it will plug right in, then add the necessary wiring to the diff actuator, diff lock position switch, control switch, etc., and it should integrate relatively easily I would think.

It certainly would be about as easy as coming up with your own solution and having to wire that up as well - though you'll still be stuck with the factory engagement limitations.

Jeff

 

From the patent; it uses the current profile to determine status.
e.g.
-activated/immediate lock
-activated/delayed lock
-deactivated/immediate unlock
-deactivated/delayed unlock

 

Agreed that is what is in the patent, but I have found no evidence that they are using their patent on the Tacoma.. seems like they are just using a lock/unlock sensor switch

 

...or, evidence to the contrary; at least in practical monitoring.

Just trying to provide more context as to why we see the current values we do.

Do you believe the current to lock/unlock is solely based on the position switch?

 

Yeah, based on running the diff lock sensor wiring into the cab and using a manual switch to spoof locked and unlocked sensor, regardless of the actual lock status of the diff.

And eventually got it to throw diff lock sensor fail code (dont remember P# off my head). But that code seemed to be based on multiple drive cycles with the diff 'spoof locked' while commanded unlocked.

Couldn't connect any behavior of the ECU that made me think it was using the lock current to actually monitor lock status (like the patent references per memory)

 

I believe current is based on the states of both the control switch (overhead console) and lock detection switch (inside the diff).

Since the ecu knows the actual state of the diff lock with feedback from the detection switch it's true closed loop control based on actual position. This is the proper closed loop control technique for such a system.

As a side note the current itself is under closed loop control based on sensing the output current but the target current is based on the closed loop control that senses the locker's actual state.

What's in the patent is a control method using current to make assumptions but technically open loop system control and less robust from a controls perspective.

 

I just regeared and put an Eaton up front. The supplied harness comes with a switch but won't fit in my overhead panel but instructions say (any similar automotive style 12V DC switch can be used). Has anyone swapped out the Eaton switch for Something else ?