troubleshoot factory lockers, lights blink nothing else

[lanshark]

I just got this 93 fj80 with factory front and rear lockers.

trying to engage rear or front and rear lockers results in blinking lights, but no noise from the actuator (?), no locking, nothing else.

i've tried slow-ish speed swerves, i've tried driving for maybe 1/4 mile, both times were on gravel, no luck.

i've been doing some reading here and found things like checking voltage at the actuator, pulling it an putting 9v to it,

is this the correct order and plan of action for my situation? Additional actions?

any recommended reading material for referencing the required steps?

 

[Mr Cimarron]

Try lifting the front or back with a floor jack in your driveway. Leave in park (for front) activate lockers and then spin one wheel by hand to see if they engage. Mine took some time to work them in. I bought it from a soccer mom who said she never used them. Took me about 15 minutes of trying before they worked the first time when I test drove it. Now they lock right up.

 

[Espi73]

Is this in High or Low?

 

[none]

Are you in low? If so, is the CDL/ABS lights lit? When i bought my LC the switch for the center diff was bad as was the switch for the gear selector (that one still is bad). When shifting to low, the lights have to come on for the ABS off and CDL to allow the front and rear diffs to lock. If they do not light up, you can short out the front switch (making the truck think the CDL is locked) then you can try to lock the diffs.
If that works, buy a new front switch. Then, try to shift to low again. If it still does not light up, just go add a CDL switch (should add one anyways, i used a 4runner hazard) and go have fun.

 

[lanshark]

center in low seems to work, ABS and orange diff indicator (as opposed to the red front or rear indicators) light up.

 

[Devil's Slide Doug]

Take them off, clean them and lube them and reseal them. There a few threads that explain how to do it. Not that difficult and worth the effort.

 

[lanshark]

from reading i figured i'd pull the wires at the front locker and give them a look and test. after sometime of having the car on (key on, engine off) and the f/r lockers set to 'on' i was able to pull the plugs and test them, I am getting no reading out of the two plugs.

also, forgot to mention all fuses look ok.

i'll try to trace back the wires and find the connections on the other end.

was my test appropriate or do i need to check those wires when the engine is running or at the same time the f/r locker switch is activated?

 

[lanshark]

i also raised the vehicle and played with the wheels by the way, no luck.

but there was a change ...

i took the rig for a ride in the hills, leaving the f/r lock switch on in the hopes they would work. I also put it into low and the center did not lock, I could hear the box in the drivers side "kickpanel"(?) making noise. After several attempts the center finally locked then so did the front. after taking it out of low the front stayed on for a bit then turned itself off. from there on i was able to replicate its inconsistency in the center and front locking or not, and the front turning itself off, or not ...

so i'm guessing i need to go to the center lock and get it running consistently, check the plugs (clean / test with meter), possibly pull it? head for this other box on the drivers side and clean / meter?

 

[dagwood85]

I put mine up in the air to test the rear locker. It blinks, but it locks up solid. Also, some kind of strange voodoo happened cause after I did that the "D" light has worked ever since. Strange, but I'll take it. Luckily there are some good locker actuator build threads. I know cause I was looking for them to do mine, but now I just live with the blinking light.

 

[asutherland]

from reading i figured i'd pull the wires at the front locker and give them a look and test. after sometime of having the car on (key on, engine off) and the f/r lockers set to 'on' i was able to pull the plugs and test them, I am getting no reading out of the two plugs.

also, forgot to mention all fuses look ok.

i'll try to trace back the wires and find the connections on the other end.

was my test appropriate or do i need to check those wires when the engine is running or at the same time the f/r locker switch is activated?

Hey lanshark, here is my writeup on my CDL issue (including rebuilding the motor): https://forum.ih8mud.com/80-series-tech/597743-cdl-relay-chatter.html

I believe Landtank on here also has a great CDL writeup. Check the FAQ sticky for links. I have repaired both my CDL locker and my rear locker (several times). Water gets in them, either via a worn out seal or a broken breather hose etc, it rusts and gums them up. If you deal with it right away, you can usually salvage them before they get too bad and are permanently damaged. They're $$$ to replace, so get on it!

A couple quick points for the testing you're doing,

- CDL must be engaged before F + R lockers will even attempt to lock.

- Lockers will actuate without having the truck running. Just put the key in the last position (so all electrical comes on)

- The relay system in the kick panel sends current to the locker motors for a limited time only. If you're testing for voltage on teh wiring harness at the lockers, you need to do it as someone else turns the locker switch. It only sends current down the wire for about > 5 seconds.

PM me if you'd like a link to download the FSM in pdf format.

 

[IanB]

- The relay system in the kick panel sends current to the locker motors for a limited time only. If you're testing for voltage on teh wiring harness at the lockers, you need to do it as someone else turns the locker switch. It only sends current down the wire for about > 5 seconds.

This is interesting. When I got my truck the lockers were very slow to engage as well, but with some sawing of the wheel and weaving around on the road, and slipping the tranny into neutral, reverse, neutral, drive, etc they would eventually engage, after a couple of minutes though. How would this be possible if the current was only sent for a brief period? The signal would be long gone when they finally engaged if this was true, and the signal would need to be there for them to engage, wouldn't it?

 

[rockrod]

you are describing the exact same issues I had when I first acquired my '94 with the e-lockers.

At first, nothing worked. No CDL and no axle locks. The lights would only blink.

I installed a CDL switch and snipped the pin 7 wire on the locker ECU.

I was then able to lock and unlock the CDL without having to be in low range. About 10-15 times of locking/unlocking the CDL eventually cleaned off the CDL sensor contacts (there are two on the t-case) so that the locker ECU knew the CDL was truly locked. The locker ECU in turn would then allow the axle locks to work.

The CDL lock sensor on the top of the t-cast must have continuity when the CDL is locked before the locker ECU will allow the axle locks to work. Most owners of these trucks never use the low range and so the CDL never gets exercised.

Mine work perfectly now. I highly suggest the CDL switch (it's a 10 minute plug and play) and also the pin 7 mod - instructions for this are on the slee sight. Then you will have full control of the t-case and lockers and will be able to lock everything in high range or low range.

 

[asutherland]

This is interesting. When I got my truck the lockers were very slow to engage as well, but with some sawing of the wheel and weaving around on the road, and slipping the tranny into neutral, reverse, neutral, drive, etc they would eventually engage, after a couple of minutes though. How would this be possible if the current was only sent for a brief period? The signal would be long gone when they finally engaged if this was true, and the signal would need to be there for them to engage, wouldn't it?

The locker motors are made up of a small electrical motor (armature), which spins quickly and turns a worm gear. The worm gear loads a big hard spring which puts force onto the shaft. When the gears become lined up, (after you move one faster than the other by turning, for example) the spring pushes the shaft with the collar attached into the gear.

So what you have essentially is a brief turning of the electric motor, which loads up physical force via the large spring. Once the gears mesh, the force pushes the shaft/collar in.

Clear as IH8mud?

Practice with your CDL. Push the CDL button (or if you don't have one, put the transfer case in 4-low) and listen in the kick panel for the relay click. If the truck is off you should be able to hear it clearly. "Click, whirrr, (the elec motor underneath) click". The 2nd click is the relay shutting the current to the motor off as the diff lock tells the relay system that it's reached its "end of travel" and the spring is loaded. This will happen whether it's physically locked or not. Then when you start driving, the gears will mesh, and the CDL light will light up informing you it's physically locked.

 

[IanB]

The locker motors are made up of a small electrical motor (armature), which spins quickly and turns a worm gear. The worm gear loads a big hard spring which puts force onto the shaft. When the gears become lined up, (after you move one faster than the other by turning, for example) the spring pushes the shaft with the collar attached into the gear.

So what you have essentially is a brief turning of the electric motor, which loads up physical force via the large spring. Once the gears mesh, the force pushes the shaft/collar in.

Clear as IH8mud?

Practice with your CDL. Push the CDL button (or if you don't have one, put the transfer case in 4-low) and listen in the kick panel for the relay click. If the truck is off you should be able to hear it clearly. "Click, whirrr, (the elec motor underneath) click". The 2nd click is the relay shutting the current to the motor off as the diff lock tells the relay system that it's reached its "end of travel" and the spring is loaded. This will happen whether it's physically locked or not. Then when you start driving, the gears will mesh, and the CDL light will light up informing you it's physically locked.

Great explanation, thanks!

 

[lanshark]

ok so, the indicator switch on the cdl is bad, jumping the plug for said indicator has the front and rear locks working but even when the rear is locked the rear lock light blinks. I tried jumping the wire at the rear indicator switch but still no luck. The rear lock light is off when the rear is unlocked and blinks when the rear is locked.

where do i go from here?

 

[asutherland]

ok so, the indicator switch on the cdl is bad, jumping the plug for said indicator has the front and rear locks working but even when the rear is locked the rear lock light blinks. I tried jumping the wire at the rear indicator switch but still no luck. The rear lock light is off when the rear is unlocked and blinks when the rear is locked.

where do i go from here?

So let me get this straight... you're sure the F + R lockers SHOULD be locking? (CDL is locked)

When you actuate the F + R switch to FF-RR (both ON) does teh FRONT lock (light becomes solid) but the rear just blinks?

If so, you likely have either a wiring issue to the rear locker, or an issue IN the locker. Study this thead: https://forum.ih8mud.com/80-series-tech/551069-locker-actuator-rebuild.html

It may be as simple as removing the locker motor, opening it up, cleaning out water/dirt/grossness, re-sealing it (use RTV gasket maker on all the seals, the OEM ones will wear out after 20 years trust me...) and putting it back on the axle.

Another "easy" troubleshooting step you can do to determine if it's a problem in the locker motor or the wiring, IF your front is confirmed working, is to remove the rear locker, then disconnect the front locker (only need to disconnect the front, not remove) and plug the rear locker (in hand) into the front harness. If the shaft of the rear locker (in your hand) moves when you lock the front, then you know it's a wiring problem not a locker motor problem. Vice versa.

 

[lanshark]

So let me get this straight... you're sure the F + R lockers SHOULD be locking? (CDL is locked)

the F and R lockers should be and ARE locking

When you actuate the F + R switch to FF-RR (both ON) does teh FRONT lock (light becomes solid) but the rear just blinks?

correct, both lockers engage and the front light stays on while the rear blinks

If so, you likely have either a wiring issue to the rear locker, or an issue IN the locker. Study this thead: https://forum.ih8mud.com/80-series-tech/551069-locker-actuator-rebuild.html

It may be as simple as removing the locker motor, opening it up, cleaning out water/dirt/grossness, re-sealing it (use RTV gasket maker on all the seals, the OEM ones will wear out after 20 years trust me...) and putting it back on the axle.

Another "easy" troubleshooting step you can do to determine if it's a problem in the locker motor or the wiring, IF your front is confirmed working, is to remove the rear locker, then disconnect the front locker (only need to disconnect the front, not remove) and plug the rear locker (in hand) into the front harness. If the shaft of the rear locker (in your hand) moves when you lock the front, then you know it's a wiring problem not a locker motor problem. Vice versa.

shouldnt i be able to 'jump' the wiring on the rear locker to get the rear locker light to stop blinking? where do i go from here with the wiring?

 

[lanshark]

new rear switch installed, just in case i was missing something.

rear locker light blinks still although the rear locker engages.

where to go from here?

could there be any wiring problem related to the fact that i have no reverse lights or prnd12 lights in the instrument panel although the neutral safety switch looks good? https://forum.ih8mud.com/80-series-tech/623938-no-reverse-lights-prnd-lights-no-power-nss.html

 

[asutherland]

new rear switch installed, just in case i was missing something.

rear locker light blinks still although the rear locker engages.

where to go from here?

could there be any wiring problem related to the fact that i have no reverse lights or prnd12 lights in the instrument panel although the neutral safety switch looks good? https://forum.ih8mud.com/80-series-tech/623938-no-reverse-lights-prnd-lights-no-power-nss.html

OH, in that case it's rather simple. The sensor is independent of the actual locker motor. The sensor that tells the dash when your rear locker is actually locked is located right next to the locker motor, you need a large deep socket to remove the sensor (I can't remember the size, but it's big). You can remove the sensor without removing the locker motor. The sensor is simply a push-ball type, when you push the ball in the 2 wires leading to it become connected and the dash light will come on solid.

When I repaired my rear locker, my locker sensor was also damaged. One of the two pins on the sensor plug was rotted right off and I had to purchase a new sensor ($80).

You can test yours easily enough. Just remove the sensor using the big socket, manually push the ball in while someone else watches your dash (make sure your ignition is on, but the truck doesn't need to be running). If it doesn't go solid when you push the ball in, unplug the sensor from the harness and jump the 2 wires leading from it. When the wires are connected the dash light should go solid. If it doesn't, trace the wire all the way up to find where the break is.

When testing this it doesn't matter what the state of the CDL is, your transfer case, or anything else. IF you connect the 2 wires, the dash light SHOULD go solid, regardless of the state of anything else.

 

[lanshark]

the rear switch i mentioned replacing is the sensor you are referring to, and the wire at the rear has been jumped but does not cause the light to stay solid.

now today while in drive in high, with the cdl on i noticed the light on the dash turning off although it felt like it was still on, then when engaging the front and rear lockers the front locker light would turn off along with the rear locker light, all while the lockers were engaged. please note that the center and rear now both have good sensors. This happened while trying to climb a rocky incline, also happened in drive / low and low / low. The lights would come back on, sometimes quickly but it did not act like it was flickering.

whats going on here to recap; good locker sensors, good lockers, good lights. rear will lock and light wont stay solid, now all lights (cdl, front, rear) will turn off and on by themselves when under load but while the locks stay engaged.