Center Diff Lock still not working / Replaced actuator switch (1 Viewer)

[SpaceCaseJase]

I've looked and looked but coming up short on next steps. My '05 Land Cruiser center diff lock isn't working. Fairly common, but here's what I've done and the symptoms:

1. I've replaced the actuator switch (used the aftermarket part thanks to dealer getting me the wrong part)
2. Verified the fuse #18 is good (30A ECU-B2)
3. I don't see the dash light come on at startup, and don't see it blink when engaging the diff lock
4. I can hear the "click" by the glove box when I engage the diff lock (but see #5)
5. My test drive can tell zero difference engaged or not


The kicker is that I was able to verify the old actuator switch wasn't functional. Simple continuity test with my fluke verified the circuit is always open. Tested the aftermarket part before installing, seemed fine.

Curious about what the smart folks would troubleshoot next. Is there a center diff ecu like the 80s series? Should I try to unplug the actuator and close the circuit manually?

 

[Marshmallow]

How are you testing locking functionality? If you have jacked up the vehicle and watching how wheels turn when you rotate one wheel, having the transmission in park makes a difference to how you interpret the results! I chased my tail (and a false code reader code) for a long time before finally concluding that mine was locking and unlocking fine.

 

[SpaceCaseJase]

How are you testing locking functionality? If you have jacked up the vehicle and watching how wheels turn when you rotate one wheel, having the transmission in park makes a difference to how you interpret the results! I chased my tail (and a false code reader code) for a long time before finally concluding that mine was locking and unlocking fine.

I was testing by doing very easy drive, slowly progressing the turning radius. Zero change in behavior of the vehicle. But you're right. get it up off of all 4 and spin wheels or shaft would 100% confirm. I could deal with a bad bulb, but I'm leaning towards it being something more.

 

[Marshmallow]

Here is a link to my post back in 2017 when I was chasing my (non) issue.

Diff locker trouble shooting post

 

[GVegasG]

Center diff lock light on our 2000 LC is not working either. However it does lock. When you try to turn tight, like a circle, it will feel weird.
Also when reversing bit uphill and trying to park on the side of driveway - felt something dragging.

 

[bobliu]

I was testing by doing very easy drive, slowly progressing the turning radius. Zero change in behavior of the vehicle. But you're right. get it up off of all 4 and spin wheels or shaft would 100% confirm. I could deal with a bad bulb, but I'm leaning towards it being something more.

did you end up getting it to lock? I have the same symptoms as you.

 

[SpaceCaseJase]

did you end up getting it to lock? I have the same symptoms as you.

Unfortunately, I haven't. I feel like I need to spring for the manual to chase down how the actuator works and all the associated wiring (ecu, ground points etc). I need more knowledge as it's been beyond me (for now!). Still learning, no shame in that.

 

[saucebox]

Unfortunately, I haven't. I feel like I need to spring for the manual to chase down how the actuator works and all the associated wiring (ecu, ground points etc). I need more knowledge as it's been beyond me (for now!). Still learning, no shame in that.

LC100 Workshop Manual

Landcruiser 100 Series Factory Workshop Manual

lc100e.github.io