3RD Time... Diff Lock Stuck On (1 Viewer)

[100d ua]

Long story short the CDL on my 2000 LC has been acting up the last several months. I do not use it for this reason. Today I accidentally hit the button vacuuming the console and have been trying everything in my power to get it to turn OFF.

High/Low Forwards Backwards
Figure 8's in gravel High and Low while Punching the CDL switch
I can faintly hear the relay clicking under the glove box but its sporadic and not as much as it was before when this happened
Yes, I am certain I depressed the CDL switch
No I cannot reach the CDL actuator atop the transfer case to whack it
Yes replacing the CDL actuator is the only thing I can think of at this point $$$

I just sold my truck and don't have access to a 3rd vehicle so would appreciate the help as it's my DD right now.

Am I okay to drive it to work and hope the lights go out?

 

[100d ua]

Update; I am not hearing the relay under the glove box clicking anymore. Usually it "tries" to click as i'm driving with the CDL button depressed. But not anymore.

 

[ramangain]

So, CDL is for sure engaged? When reversing and going full steering lock, the truck wants to stop on its own?

 

[100d ua]

So, CDL is for sure engaged? When reversing and going full steering lock, the truck wants to stop on its own?

Yep.

Apparently I am the only one that has ever had this problem because I am finding absolutely no threads about this anywhere.

 

[Ayune]

When you were hearing the relay clicking under the dash, was it in response to you pressing the button? Or was it clicking on its own while driving?

 

[100d ua]

When you were hearing the relay clicking under the dash, was it in response to you pressing the button? Or was it clicking on its own while driving?

It was clicking on its own while driving with the button depressed. Sounds like it was trying to disengage the actuator.

it’s not clicking at all anymore.

I am going to drop the cross member and remove the unit when I get home from work tonight. It’s well past long enough that I get this issue sorted.

 

[neoworm]

Just replace the switch on the tcase under the truck and itll be fine. Its a bit fiddly to get to but a cheap and ez fix. Pretty common issue on a lot of Toyota 4wd.

 

[100d ua]

Just replace the switch on the tcase under the truck and itll be fine. Its a bit fiddly to get to but a cheap and ez fix. Pretty common issue on a lot of Toyota 4wd.

I thought the switch issue only presented symptoms of the lights not appearing on the dash indicating that the CDL was engaged or not. Not that it was responsible for keeping the CDL locked.

 

[neoworm]

The ecu needs the switch input in order to engage/disengage the cdl. 99 times out of 100 that switch is the issue.

 

[neoworm]

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[neoworm]

Its part 84222c on the diagram. At least it is on my 03. Or maybe the one next to it. Cant remember exactly now.

 

[neckbone]

I was having trouble with mine sticking. I could get it to disengage, but it took alot of forward reverse neutral. Once I changed the diff fluid, it engages and disengages like a dream. Might want to give that a try if you can't remember when it's been done. Takes about 20 minutes under the truck. There's a "how to" in the FAQ's.

 

[Ayune]

The ecu needs the switch input in order to engage/disengage the cdl. 99 times out of 100 that switch is the issue.

This is incorrect. The detector switch does not provide input to the ECU. The switch only illuminates the dash light.

I thought the switch issue only presented symptoms of the lights not appearing on the dash indicating that the CDL was engaged or not. Not that it was responsible for keeping the CDL locked.

Correct.

 

[neoworm]

Ya you guys are wrong but whatever. Good luck.

 

[Ayune]

Ya you guys are wrong but whatever. Good luck.

The wiring diagram does not lie.

 

[100d ua]

The wiring diagram does not lie.
View attachment 2382041

So what do you recommend? Removing the actuator?

 

[Ayune]

It was clicking on its own while driving with the button depressed. Sounds like it was trying to disengage the actuator.

If it was clicking on its own then one of the switch inputs to the ECU is flaky. There are three:
1. “L” position switch. If this was flaky you may also see other signs like changing transmission shift points.
2. Motor travel switch inside the center diff lock mechanism itself. Kinda like the ‘park position’ switch in your wipers that senses when the motor has completed its prescribed travel.
3. The CDL dash switch that you can press. This is the a likely culprit because the switch contact may be dirty and essentially turning on and off while you drive. This would only happen when the switch is pressed in. I’m curious if you ever heard the sporadic clicking while the switch was in the OFF (out) position?

The fact that you can’t get the CDL to disengage may be because of old diff fluid as @neckbone suggested. But the lock motor must first be in to the “unlock” position before it’ll even try to release if it’s sticky. The ECU needs to tell the motor to back off.

 

[100d ua]

If it was clicking on its own then one of the switch inputs to the ECU is flaky. There are three:
1. “L” position switch. If this was flaky you may also see other signs like changing transmission shift points.
2. Motor travel switch inside the center diff lock mechanism itself. Kinda like the ‘park position’ switch in your wipers that senses when the motor has completed its prescribed travel.
3. The CDL dash switch that you can press. This is the a likely culprit because the switch contact may be dirty and essentially turning on and off while you drive. This would only happen when the switch is pressed in. I’m curious if you ever heard the sporadic clicking while the switch was in the OFF (out) position?

The fact that you can’t get the CDL to disengage may be because of old diff fluid as @neckbone suggested. But the lock motor must first be in to the “unlock” position before it’ll even try to release if it’s sticky. The ECU needs to tell the motor to back off.

The fluid was replaced 3 or so months ago and I never heard the clicking noise from the glove box while the CDL switch was in the off position.

sorry, to CLARIFY; the clicking noise was present with the CDL switch depressed AFTER I had accidentally clicked the CDL button and then so began trying to disengage the CDL lock.

The clicking noise has never been present when the diff lock was disabled prior to me accidentally turning it on.

 

[neoworm]

Go change the switch and if it doesnt work you can say I told you so. Haha. When it does you can buy me a beer sometime.

 

[Ayune]

The fluid was replaced 3 or so months ago and I never heard the clicking noise from the glove box while the CDL switch was in the off position.

Ok, it sounds like your CDL dash button is faulty. And it’s not just a simple button, it has circuitry on it to electrically “latch” on or off (see pic below). This circuitry may be toast and not telling the ECU that the button is “out”.

To test this you’d need to unplug the CDL (and hazard) switch module and short two other wires together on a connector behind the climate control panel. I just went through this when relocating my CDL and Hazard switches.