Rear Lockers *Not The Same Old Question* - Troubleshooting Step 2 (1 Viewer)

[grahamo]

Actually, I'm sure it's been covered before, I just can't seem to find the right search keyword combo.

My center diff locks up quickly. Dash light + ABS lights come on fast. The front's work great, too - the light blinks once and then locks. But the rear indicator light will not stop flashing.

I have driven in circles, left and right, big and small, slow, slower, and slowest, firm dirt and soft dirt - no luck. Last night I shut off the engine in 4L and was able to hear the rear motor hum as I switched the rear diff on and off. It would go about 1 second and then stop positively - as if it had done something.

I am on a bit of a vacation - all my tools (e.g. jack) are 500 miles away - so I can't lift it and spin the wheels manually.

Two questions:
(1) I just bought a multimeter - is there a sensor I can test? Perhaps it's locking and it doesn't know it. I see two connectors, a 2 pin and maybe a 5 or 6 pin? What am I looking for?

(2) If #1 isn't the problem (or is an asinine question) - what's my next step (besides driving in more circles)?

 

[Adam B]

Having just gone through a rear locker electrical repair, I'll offer what I can.....

My rear locker light would also just flash, front worked fine. For a long time I assumed that the sensor was bad but after a recent "stuck" moment I decided to test it and I discovered that my motor was not doing anything and it was not locking.

To test if it's locking, put the rear end on jack stands, turn the ignition ON (engine off), lock the CDL, turn the rear switch to lock, listen to the motor do its thing (it should only do it for a second or two at most until it hits the limit switch). Grab one rear tire and rotate one way then the other. If it's locking it should do so pretty quickly and the two will be forced to rotate the same way. If it isn't locking the two rear tires will rotate in opposite directions.

If it does lock and the light still flashes, your position sensor isn't working. It's the 2 wire connection. Really, it's only there so you know that it has locked. It doesn't communicate with the locker ECU.

Check FJBen's post HERE to see which wires are which.

The 5 wire connection (+1 empty spot) is what actually controls the motor. The two heavier gauge green wires provide +/- to the motor. They switch polarity depending on what the locker ECU is telling them to do. The white/black wire is a ground and the other two are for the limit switch in the motor. One of them is normally grounded when the motor is one way (#5, unlocked), the other (#6) grounds when the motor reaches the limit the other way (unlocked). note that #5 and #6 are referenced to FJBen's diagram in the previously mentioned thread...

In my case, the white/black wire to the motor was cracked inside the plastic connector. Gently tugging on them all didn't reveal the problem because of the rubber grommets they use to seal around where the wires enter the connector. Without that ground, the ECU never saw the #5 wire grounded and wouldn't send power to the motor. I tested the "9V battery method" which is simply hooking up a fresh 9V battery to the two heavy gauge green wires to make the motor turn and my motor worked. One way locks, switch the wires to unlock. Giving the rear tires a quick rotation by hand caused them to lock right up. I would suggest only doing this for a second and not leaving it hooked up longer than that. The motor can only turn a small amount before it reaches a limit but without the limit switch in the equation (or the ECU) leaving the motor powered up will probably kill it fairly quick.

So after getting that all sorted out my locker would engage but the light would still flash. It turned out that one of the wires to the sensor was also broken. After wrestling the connector apart I found nasty green corrosion inside and one of the male pins had broken off the sensor side. It did so flush with the inside of the plastic connector and as far as I can tell there's no easy way to disassemble the sensor so I ended up buying a new one.

Now, everything works.

If your motor turns but the locker still isn't engaging, then it isn't a wiring issue and you're going to have to start pulling stuff apart. There are some other good threads about that. Make sure you read RavenTai's post about how to reassemble everything

 

[Adam B]

Also, if it is actually locking but the sensor is bad the light will flash forever but it should be really obvious that it is actually locked. If you try it on pavement with your windows down you'll hear and feel the tires scrub as you turn. Even on gravel it's really easy to tell. The inside tire will leave a strip on the gravel as it gets dragged around.

 

[LINUS]

A bit of a echo of the post Adam B stated, but how about you just stop at the rear locker position & run it in a figure 8 pattern for a good long while - you sound like you had it functioning at some point before, so you know the "sticking" feel & would know when locked & tried turning at full lock in either direction.

Also, I posted it before & can't recall the exact wire colors (search my user name & "e-locker & 9v battery" the post might show up), but you can hit the actuator with a 9v battery & "wake it up" if it's something like moisture in the actuator housing - if nothing happens the first try, you reverse polarity & try it again - getting a 9v worth of current straight to the actuator seem to help when an older, possibly contaminated actuator is acting old & arthritic.

Like Adam posted, -- are you positive the locker isn't working & the pin switch just isn't giving signal to the light in the cluster?

Cdan just posted in the most recent locker thread that it's extremely normal due to design that the FR is much quicker than the RR as far as locking time -- are you positive you gave it more than ample time to do the job?

Also, the EWD for a '96 was posted here recently - worse come to worse, DL the manual & it's a snap to figure out the locker section IIRC it was "Birf Mark" that uploaded it - I may have the user name incorrectly typed as for upper case/lower case, but it was that user name in some form if you look him up/pursue it that way.

 

[grahamo]

Thanks Adam! Great information.

It looks like my lockers ARE locking. I was able to use the tire jack and a pile of firewood (like I said, I'm camping) to jack both rears off the ground. Without the the switch engaged they would spin opposite of each other. I engaged the switch and and soon as I gave it a little spin the rears would lock up. So glad!!!!

I'll check the two-wire connector as you suggested. Thanks again.

 

[grahamo]

Thanks Linus. I read up as much as I could before I posted and found a lot of tips. This is my first LC, and I've had it for all of 10 days.

I saw the EWD, too, and am going to use it to hunt down my Parking "Brake" light that won't turn off *most of the time. It's not the switch, so it sounds like I'm going to trace it back looking for shorts.

 

[grahamo]

I was able to confirm that the electrical for the engine-side connector is in tact. My multimeter showed much different readings depending on the switch position, and when I jumped the pins the light stayed on.

So the problem is the sensor itself. Any thoughts?

 

[LINUS]

So the problem is the sensor itself. Any thoughts?

You're golden. When you get home, buy a new one. Search with Napa (the parts store) & something like "diff locker" "e-locker" "factory locker" & you can find a thread where they are 2/3 the cost of OEM one - if you want save a few $$$, aside from that IIRC when I bought one last year OEM was ~$35 bucks.

 

[grahamo]

Try 1/3 the cost. There's an AC Delco (part #E2209A) where I am - I'll give them a try tomorrow.

Here's that post: https://forum.ih8mud.com/80-series-tech/446641-replacement-84222-12010-switch.html

Thanks!!!

 

[grahamo]

I wanted to finish off this post for anyone with this problem in the future.

I purchased the switch ("sensor") for the rear differential locker - part numbers listed above. I tested the old switch when I removed it and found it to work as expected - it would complete a circuit when depressed even a little bit. However, it would not indicate that the differential was locked even when it obviously was. After installing the new switch the differential did indicate that it was locked.

So anyway - if you pull your switch and it does complete a circuit when depressed it still might be the case that it needs to be replaced. (I should note that the pins on both connectors were clean). When diagnosing be sure to include another test: jumping the engine-side connector at the differential - this completed the circuit and the light stopped flashing, indicating to me that something was wrong with the switch.

 

[robustbambi]

I tested the "9V battery method" which is simply hooking up a fresh 9V battery to the two heavy gauge green wires to make the motor turn and my motor worked. One way locks, switch the wires to unlock.

I bought a 62 with 9.5" e lockers in both diffs which im converting to cable lockers with chilkat products, but i wanted to test the actuators to ensure they work before i sell them. To test the actuators with a 9V battery, do you ONLY attach the + and - battery terminals to the two green wires? or do you need to additionally power or ground any of the other prongs. Ive been looking at all these threads and now im just one extremely confused 60 series owner lol.

 

[robustbambi]

nvm. Tested both and they work beautifully