Rear differential locker

Hey guys, new to the forum. Purchased my 16 Trail Edition couple months back, and made the horrible mistake of not crawling underneath. Long story short, tons of rust. Anyways bought it 8 hours from home, month and a half later decided if check out the locker and got nothing. (of course the dealer I bought it from was zero help) Didn't engage, no flashing diff lock light. In fact, the light in the dash didn't even come on.... At all, not even when I first turn the key to the run position. All the local dealer told me was it needed a new actuator to the tune of $2k. I'm a bit of a DIY'er so, I pulled the actuator and it's an absolute train wreck. Obviously I need to replace the actuator itself. But the fact that the diff lock light doesn't come on at all still worries me. Any thoughts or suggestions would be greatly appreciated.

 

Not sure if there's a fuse for the rear diff lock. But I'd start there.

 

Is that a hole in the actuator housing?!?! Yikes! How bad is the rust every where else?

I just checked my dash lights and noticed the locker annunciator does not light up during startup. So that shouldnt be taken as any sort of sign.

Just to make sure, are you engaging the locker in 4lo? It has to be in 4lo for the locker button to do anything.

once in 4lo, you should hear a relay click in the passenger dash area immediately when you push the button. It’s actually two clicks. Same clicks when you push the button to turn it off. That should tell you that at least the signal is getting out of the cab. You could also put your phone recording under the pumpkin. A working actuator will make a very noticeable gear sound if the mic is close by.

That actuator looks pretty rough, I’d replace it yourself first, since you already did half the work. There are vids out there on how to do it. There’s no way that part costs 2k.

 

I found it for $379. I figure it obviously needs replaced so could start there anyways. It was in 4Lo, and I heard no solenoids clicking. Check all the fuses pertaining to the 4wd system and all checked good with a volt meter. I wonder if that actuator being so bad if all the contacts made inside are also bad causing zero feed back to the dash light. Any idea which fuse that actuator would be on? And to share your first question yeah that's a hole in the actuator. Love the 4runner just wished is bought different one. Rust is pretty bad, gonna get to work on it as soon as we start getting some decent weather.

 

Maybe that’s possible….Either way, like you said, that actuator has to get replaced. But make sure the harness isnt an unsalvageable mess, just so you know what you’re getting yourself into lol.

Maybe someone else can chime in with regard to the actuator fuse location.

edit: that hole in the actuator is kind of bugging me. Did it compromise the seal where the gear goes into the diff? Be careful not to knock a bunch of gunk into that opening into the diff and keep it sealed off while you’re working. A diff oil change is probably called for as well

 

It's still sealed off, but will definitely change the fluid when I change the actuator. And I'm with ya on the plug, kinda worried a bit but won't be able to look at it for a while as I've just had surgery the day after I unbolted the actuator lol.

 

Get better soon! In the meantime, I should really make sure my actuator is not caked in mud lol.

 

When I see photos of the underside of a 4Runner that look like that I feel so bad for folks who live in climates that cause that kind of corrosion damage, and at the same time very thankful for living in the desert southwest. I wish there was some way to swap some of our constant sunshine and zero humidity for some of your abundant rainfall.

Sorry you had to discover this after the purchase, and best of luck fixing the locker actuator.

 

Seeing the rust damage on the underside of that 4Runner is heartbreaking, especially knowing it is a post purchase surprise. I feel bad for the OP.

Hope you get your locker sorted out and can wok on treating the rust problem so you can enjoy your 4Runner.

 

Thank ya much, McSpazatron and yeah man the rust on these things can be no joke! Gonna get mine all wire brushed and fluid filmed or wool waxed. I appreciate your help!

 

So replaced the actuator, I can hear a relay behind the glove box, and still no light on the dash for the diff locker. Is there a fuse or something in missing? Thanks y'all, just stumped

 

Are you in 4Lo?

 

Yes sir. Light doesn't even come on. Doesn't light up solid or even flash

 

Can you verify if the actuator makes a noise when you click the diff lock on? It should make a electric motor noise, for maybe a bit short of a full second. The noise should happen even if the diff isnt entirely engaged.

At least that would tell you if the signal gets to the actuator.

Any electrical experts here with ideas on any other fuses that feed into the 4lo / locker?

 

I was just thinking of this a little bit ago, thinking maybe the dash light is just out? Lol fat chance I know but who knows. But if it doesn't make any noise, at least that'd tell me that is not getting the signal and give me a place to start. If the relay is clicking, is it safe to assume it's good? Also would it need to be running or could it possibly function with the key in the run position and the car in neutral? Just trying to eliminate extra noises. As bad as the actuator was corroded, I thought sure the pins on the plug would be shot, but they were like new.

 

I'm just stumped why the light isn't even coming on. I'd understand if the light was flashing and the actuator wasn't working that makes sense. But ... No light. My wife swears she saw the indicator when we were first tried the locker....I think she's nuts, but maybe. After seeing the actuator though I could absolutely see where it could short something and blow a fuse.

 

Have a look at the video below. I know it’s for a different year and species of Toyota but I bet there’s a lot of applicable info. This guy jacks up all 4 corners to see what’s going on and diagnose.

 

Check for power & ground at the actuator connector with switch on/off. Very easy test that will fill out wiring issue.

With the severe amount of corrosion under your 4Runner, I wouldn’t rule out corroded wiring.

 

Thanks y'all for the replies and direction, I'll definitely give these things a go tomorrow. A friend of mine was able to dig up this blurry ass schematic, and I'm just trying to figure out which colored wires should be ground and which ones I should have voltage. Or if y'all know the pin layout that'd be awesome too lol! Thanks again so much for all the help!

 

I’m wading through the wiring diagram. Forgive me — I’m not unfamiliar with wiring but I’m unfamiliar with this format — it appears that there are two connectors back by the differential lock. One is marked Rear Differential Shift Lock Actuator (6 pins) on the diagram and then another marked Rear Differential Lock Indicator Switch (2 pins). I don’t know if the switch is a separate component or not, but it could be that the locker is locking but the indicator is not lighting up b/c of a faulty switch. If you’re like me you probably don’t have 4 jack stands lying around but I think it would be worthwhile to borrow some and then go through the steps in the video above to see if the locker is working

 

I'll have to see what I can do. My very first thought was a bad switch, but that sucker was like $110 pretty steep just to try. Then I had the thing into a dealer for a separate issue and and ask if they could take a look at it and they said the actuator was bad so that's where I'm at now but now the actuator is new and nothing has changed lol

 

Something has changed. You hear the clicking relays, where before you didn't. Correct?

@Captain Spalding mentioned the 2pin indicator switch back there. If that exists, then Im betting the actuator is actuating, but that switch wiring isnt getting a signal to the dash.

It should actuate with the trans in neutral and the key set to ignition on. Put your phone under the diff, start a video recording, then push the switch. Replay your video and you’ll hear the actuator clear as a bell, if it’s working.

Hopefully it is and you can focus on figuring out the diff indicator switch wiring.

 

I don't recall hearing the relay before, no. But there's only one plug, and a rubber hose which if I'm not mistaken is a vent. I will definitely check the actuator though. I appreciate you all. It's 3am and this thing is on my mind lol it's driving me crazy. It's not really that I have to have it, but it's one of the main reasons I sought out the trail edition.... I can't let it win!

 

Victory will be yours…oh yes. From that point on, you shall be known as the whisperer of e-lockers, the wise oracle, sought from afar for your knowledge.

It occurred to me that figuring out the location of the actual indicator switch is important. It might be part of the new actuator, or be something separate inside the diff.

If it’s separate, it could be the switch, and not the wiring.

 

Ok guys...... So the actuator is working and locking the diff. Still no light, but did find the two pin plug that Captain Spalding was speaking of, it's located just at the top of the diff above the actuator. So, I disconnected the battery, and unplugged it. Sprayed both the plug and actuator switch (on the diff) with contact cleaner. I blew everything out to insure everything was evaporated, and now.... You're not gonna believe this...... But when I engage the locker, the abs light comes on disengage locker abs light goes off..... Did I mention the diff locker light still is a no show? FML lol

 

Attached: find a cut-and-paste PDF file of the Rear Diff Lock Wiring.

 

Well at least the locker works!!!

Does it looks like the switch is in the diff itself? Maybe the switch itself is faulty.

Regarding the abs light, not completely sure, but I think abs is supposed to disengage with the locker and/or 4lo. Lemme check later to verify.

 

Yes sir, It is in the diff itself. And yeah, if nothing else I can use the abs light as an indicator lol. Thanks Captain Spalding for that info!

 

Definitly could be the switch then. I would imagine the switch senses when the rack moves to the lock position (after the actuator turns it to position). That would give you a blinking locked indication. But these lockers dont lock instantly. Sometimes you have to turn slightly and then you’ll hear a “click” when everything lines up and falls into place. Once that happens, you get a solid red “lock” light on the dash.

same for unlocking. When you press to unlock…it will blink. Sometimes it goes straight to turning off completely, but more often than not it will keep blinking because everything stays locked until yiu do a little dance and it falls out of locked.