Locker Won't Engage

Here is what I know...

Turn knob to 4WD, 4WD engages (as well as dash light illuminates steady)
Push and turn knob to 4LO, 4LO engages (as well as dash light illuminates steady)
Push locker button, locker DOES NOT engage and the dash light just flashes

What I have tried...

Driving and turning in 4LO with locker button on (light flashing)
Driving forward and back in 4LO with locker button on (light flashing)
Jacking up rear wheels and manually rotating each wheel with locker button on (engine running, in park, 4LO engaged)

What happens...

Locker never locks
Rear wheels spin freely in opposite directions when in the air
I become disappointed and frustrated by this flashing light

Any suggestions on what the next diagnosis step might be...?

Test 12v at the actuator plug?

Looks to me that wire LG and LG-R should get 12v depending if switch is on or off. I assume truck will need to be in 4LO for any signal at all.

Pull the actuator and bench test?

Quick 12V blip to LG and LG-R to see if the motor moves? (Making sure W-B is grounded of course)

 

forgive me for asking but are you in neutral when you go to 4low then push the locker?

 

Yes... neutral to get into 4LO... then driving in 4LO to try and get locker to engage.

 

I had a 2005 and the current 2010... The trick if it doesn't engage (blinking to solid locker light) stopped or rolling forward slowly (which it does sometimes), is to turn the wheel all the way to the left (or right) and then roll slowly... The locker engages every time in just a couple of feet doing that.

 

Makes sense...just like the front axle disconnect, if the gears/splines aren't aligned just right it won't engage.

 

Tap the elocker servo with SFH...perhaps just sticky? Use it much? I found mine to be like other things...the more you use it, the easier it goes in.

 

You may have missed where I said I have driven figure 8, circles both directions in reverse and drive with no luck.

 

I used to have a 03 prerunner and sometimes had trouble with the locker engaging. I would drive ahead slowly or reverse slowly and it almost always went in eventually. Was annoying sometimes for sure.

 

I did not say anything about driving a figure 8, circles, or reverse.
I said from a stop, with the button pressed (blinking locker light), turn your steering wheel all the way to one direction (right or left, but just one) and then slowly move... In less than 5 feet the locker engages. This has worked every time when going straight from a stop hasn't worked.

 

I am having the same issue but I have aligned the locker and the locker still won't work.
I checked to see if the locker was getting power and it wasn't. The switch is giving power and the wires are fine I think my computer for the locker is bad... I'm going to go to the dealer to have then diagnose the issue. If the locker is bad I will replace with an ARB locker.

 

Thanks for the clarification. I gave your technique a try and unfortunately locker light still flashes, won't engage.

Guessing I have an electrical or actuator issue perhaps.

 

Go to LG and LG-R at the connector on the diff and see if you've got power and ground. If you do then you know the locker is being commanded to engage, and youll know that the problem is inside the diff.

If you dont have power/ground present then you have a switch/ecu/wiring issue.

Testing for that command signal right at the diff connector will allow you to split the system in half

 

I am assuming 12V will only be present when in 4LO and will alternate depending on whether the switch is in the on or off position, correct?

 

Yes.. probably..

When you push the switch to activate the locker it sends a request to the ECU. The ecu looks to see if you're in 4lo and then sends a command signal (12 volts) to the diff lock motor. The motor is supposed to move the linkage and engage the locker. If the linkage/locker engages fully, a little push button switch (similar to a manual trans reverse light switch) gets pushed and tells the ecu that you had a successful engagement (the light stops blinking and goes solid).

Are you sure the locker is not engaging? Do the wheels bind when turning? Its possible the locker is in fact engaging but the little switch is stuck and the ECU thinks its not engaged when it actually is

The whole point of checking for a command signal right at the diff connector is because if you have a signal present then you know that the ecu is happy with its own requirements and it is trying to engage the locker. At that point you could call up ecgs and get a ready-to-go locker coming!

If you dont have a command signal then the ecu is not happy with what its seeing. Eg, not seeing a command from the dash button, not seeing that the t-case is in 4lo, etc

 

Reasonably sure. No matter what I do one rear wheel will spin under load, looking for traction and no wheel scrub while turning.

I had an ARB locker on a previous 4Runner so I am relatively familiar with how a locker feels when it's working.

 

I would get a dmm, and test power/ground right at the connector. Dont try to check ground through the frame. Honestly, out of those 2 wires, looking at the above diagram, i cant tell which is power and which is ground but it doesnt matter. If the dmm leads are switched and voltage is present, it will just show 12 volts or negative 12 volts. Doesnt matter because you know the locker is getting a command to engage

 

Well... crawled underneath and pulled the plug, ready to volt test when I saw the ground wire was busted right at the plug. Reconnected and now the locker light stays on steady. Will try and take it out and see if it is truly working. Would be a fantastically cheap fix... and I am generally not that lucky.

 

At least you found it, thats gotta be it!


Looking at the diagram again, that white and blue ground is probably the ground for the switch that tells it when it is engaged. I think the two wires going to the motor get their polarity reversed so the motor can spin in both directions. Make sure any other frayed wires get cleaned up and repaired while you're in there

 

That solved it... works perfectly now.

Thanks everyone for your input.

Now to figure out this "Locker Anytime Mod for Dummies"...

 

That green with red stripe wire looks in bad shape too, and the whole connector, really