Center Diff Lock - Troubleshooting (1 Viewer)

[sierra1boy]

This one has me stumped, any advice would be appreciated. I’ve read just about all the related posts on here and I’m going cross eyed looking at this wiring diagram currently. Here’s what I have and what I have done so far (94’ triple locked but missing front locker):

My rig doesn’t have the center diff button and relies on being put into low range to activate the center. When I do this no indicator light comes on. When I life a wheel it spins with the same resistance as when it is in high range. When I drive in a circle I don’t feel the tugging/binding that I’m familiar with on other vehicles.

-both fuses 10 and 30 pass test
-i get voltage at these fuses locations when the ignition is on position
-all three sensors on the transfer case failed bench test and have been replaced
-shorting the dash indicator at the transfer case does light up the dash indicator
-the black box relay in the kick panel passes the bench test
-when I put it in low range and listen carefully I do not hear the relay engaging

The only thing I can think of is that the system still doesn’t know it is in low range but I’m stumped..

 

[ppc]

-shorting the dash indicator at the transfer case does light up the dash indicator

Be more specific on which sensor on the transfer case you are shorting, across both terminals or to ground?

-when I put it in low range and listen carefully I do not hear the relay engaging

Have you shorted the terminals together on 4Low position sensor connector at the transfer case?

 

[sierra1boy]

I shorted across both terminals of the sensor at the front of the transfer case that I think signals the dash light.

I have not tried to short across the low range sensor on the back of the transfer case. If I try that what am I looking for?

Thank you

 

[BTLSHP]

Are you hearing the relay in the kick panel when you shift to low range? I heard it pretty distinctly when I when trying to figure out why my center diff lock light would only flash. That the led me to the sensor.

 

[HuyFZJ80]

I’m in the same situation as you. I’ve ordered a center diff dashboard switch to see if that might work. When I have a moment, I’m going to put power directly to the diff actuator motor to rule that out as well. Good luck!

 

[ppc]

I shorted across both terminals of the sensor at the front of the transfer case that I think signals the dash light.

I have not tried to short across the low range sensor on the back of the transfer case. If I try that what am I looking for?

Thank you

Did you short the terminal on the connector or the sensor itself? Shorting the sensor does nothing.
If it was on the connector then you either have a burned out or missing bulb in the dash or the wiring harness has a problem.

With the engine off, key in On position, by shorting the connector on the 4Low should activate the center diff lock, should hear the relays click, and the CDL actuator should then lock the transfer case.

You stated you read just all the related posts. All this has been documented in at least 100 threads. Start reading again, there is nothing unique about your problem.

 

[jonheld]

This one has me stumped, any advice would be appreciated. I’ve read just about all the related posts on here and I’m going cross eyed looking at this wiring diagram currently.

Pages TR-54 through TR-56 in the 1994 Toyota FSM gives a brief and easy check of the components.
Always refer to the manual first.

 

[sierra1boy]

Got it! Finally got it working. I still don’t know what the issue was but I installed a center diff button and that cleaned it up. I’m bummed that my troubleshooting skills didn’t get me there but I’ll take the victory. Now it’s on to the rear locker. I couldn’t get it to engage

 

[98 SNAKE EATER]

Got it! Finally got it working. I still don’t know what the issue was but I installed a center diff button and that cleaned it up. I’m bummed that my troubleshooting skills didn’t get me there but I’ll take the victory. Now it’s on to the rear locker. I couldn’t get it to engage

So with the switch installed, the center now locks up AND the light shows up on the dash?

 

[sierra1boy]

So with the switch installed, the center now locks up AND the light shows up on the dash?

Yep, sure does. And when I put it in low range without the button pressed it now locks the center as well

 

[sierra1boy]

I was just thinking of a related post that said the ABS light also should come on when you lock the center, however, only my center lock indicator comes on. Is this a problem or is that only on certain year cruisers?

 

[98 SNAKE EATER]

I was just thinking of a related post that said the ABS light also should come on when you lock the center, however, only my center lock indicator comes on. Is this a problem or is that only on certain year cruisers?

Yes, ABS should also come on.

Are you sure the center is actually locking?

Do you feel the drivetrain binding up when you turn?

 

[sierra1boy]

Yes, ABS should also come on.

Are you sure the center is actually locking?

Do you feel the drivetrain binding up when you turn?

Pretty sure because the CDL indicator comes on and it feels and sounds different. I only solved it today so next weekend I will lift a front wheel and check

 

[sierra1boy]

Maybe mine doesn’t have ABS?

 

[98 SNAKE EATER]

Maybe mine doesn’t have ABS?

Well, it was optional in 93 and made standard in 95
I've honestly never seen an FZJ without it though
Does it have wheel sensors?
Also, does the ABS light come on with the rest of the dash lights when you turn the ignition on?
Could be a blown ABS bulb (if you have it)

 

[sierra1boy]

Mine is a 94 and I’ll have to look up some pics to figure out where those wheel sensors are. As for the dash, I just went out there and turned the key to the on position and these came on:

 

[ppc]

@sierra1boy, when you installed the dash button did you remove the one wire jumper to be able to plug in the switch?

 

[sierra1boy]

@sierra1boy, when you installed the dash button did you remove the one wire jumper to be able to plug in the switch?

View attachment 3789148

 

[sierra1boy]

Yep, that thing was weird looking but I figured out that it was acting more like a cap and removed it

 

[HuyFZJ80]

Glad you were able to get it figured out. I got a center diff dash switch installed this past week, but it didn’t resolve my issue. Guess it’s more trial/error for me