CDL relay chatter (6 Viewers)

[asutherland]

---SOLVED---

I know, another CDL thread.

I've read all of them. And performed most tests on Troubleshooting the Toyota FJ80 Land Cruiser Center Diff Lock (CDL) | Pacific Northwest Backroad Adventures

1993 cruiser. I have the CDL switch installed and done the Pin7 mod to allow me to turn CDL off in 4-low. Both have worked for a long time now.

When I press the CDL button, I get major relay chatter coming from the kick panel. I assume from the transmission relay box, which is why I checked it. It looks flawless, and I did all the relay box checks on the site above.

Eventually, if I leave the button pressed in, the locker actually engages. Used to take only a couple seconds or a few feet of wheel travel on the road, but now it's taking a couple minutes. (after the relay chatter ends)

Same situation when unlocking. Except yesterday while I was troubleshooting the damn thing wouldn't unlock for the rest of the evening, even when I drove a few KM. I finally got it to unlock by pulling the CDL fuse for a second and then cycling the button once more.

I did read somewhere that the relay box gets it's ground from the motor itself, allowing the motor to tell the relay to shut off at the end of travel. If that's the case, then it could be also causing the relay box to chatter.

I've rebuilt my rear e-locker before. It wasn't fun. The CDL one appears to be even worse, because it's tucked up high on the transfer case and I've read you need to drop the case to even get at it. I am hoping it's not the motor, but........ *sigh*. I guess I have to get under there, scrape off the 20 years of crud and check wiring / take the motor off.

Any other ideas? I'll post up results as they come.

 

[elhombre]

It may be as simple as the relay itself is going bad. The contacts may have developed crap on them over the years. Maybe the contacts inside are burned up. I admit I haven't done this myself, but if you can find the same relay from somewhere else in the truck and swap them out to see if the problem continues, then you may end up a little closer to the solution.

 

[BlackLS1]

i have the exact same problem. mine does it sometimes when in 4 low, i hear the box clicking and the diff lock light is turning off and on with the rythem of the clicking.

 

[LongDuck]

While I admit I'm kinda new at this, what you describe sounds to me like a bad connection; have you checked your harness going into the CDL control box by the driver's footwell?

In terms of ease of access, I'd start there, since it's a lot easier to pull that harness, reseat it and try it out, than it is to drop the Transfer Case.

If nothing else, and it still does it after you check the CDL control box, at least you've checked it and are approaching troubleshooting with some logic in mind. If it's our CDL control on the transfer case, there's no way around it.

The fact that it's clicking repeatedly and the dash CDL light is intermittent tells me that it's probably a wiring connection, but have a look. Good luck,

 

[rove_mcanus]

Both the motor and cdl light ground to the engine block, but the light is independant of the motor. So the issue could be a faulty earth. I would try running another earth to the wiring harness near the cdl motor before going to the bother of pulling it out.

 

[ironhippy]

I have a similar issue, but it's intermittent. Seems to happen more when the truck is hot (as in after driving on the highway for 30 - 60 minutes)

I need to start checking grounds.

 

[asutherland]

I've checked the CDL relay box and the harness going to it, both are OK. The CDL box passed all Mr. T's checks in the FSM

Using your 9 volt battery and your positive and negative test leads, apply battery voltage to the CDL relay terminals as follows:

Positive to 6 / Negative to 5 = Continuity 1/3, No Continuity 1/2
Positive to 7 / Negative to 2 = No Continuity 9/10
Positive to 9 / Negative to 10 = Continuity 3/4, No Continuity 2/4

Troubleshooting the Toyota FJ80 Land Cruiser Center Diff Lock (CDL) | Pacific Northwest Backroad Adventures

I then crawled under and found the locker motor harness, un-clipped it and checked and cleaned the connection, re-seated and tried again - no change. Clatter clatter clatter.

I then tried applying a 9 volt batter and ground to pins 2 and 3 (in both directions) as specified in the link above, in attempt to get the motor to work independently. Nothing happened. Not a click or whirr or anything.

Rove, do you know where the ground to engine is? Is it part of a larger ground system or independent? Nothing else electronic in the truck is malfunctioning.

Also, just to clarify - the CDL light on the dash seems to work fine. Once it finally locks (or unlocks) it shows clearly on the dash. The dash light does not falter at any point in time.

 

[asutherland]

Looks like I am dropping down the transfer case tomorrow... :\

 

[BlackLS1]

let us know how it goes.

 

[asutherland]

Before I got into it, I checked the resistance across pin 2 and 3... 14 mega ohm. Oops. I also found where the water got in... the breather hose was hanging off, completely rotted and frayed. Checked the transfer case and transmission hoses, they were fine...

So, let me get this straight... the e-motor breather and x-case breather are T'd together, then run back along the top of the transmission (side by side with the trans breather) and then both lines tie in together into near the top of the transmission dip stick tube?

 

[asutherland]

Well, got it fixed. Details and pictures to follow. Was indeed the locker motor.

 

[asutherland]

Ok, so here's the story. I took a couple clear shots of the locker motor to help anyone else out who needs to remove it.

I dropped the 2 skid plates (including the very heavy 1/4 inch steel Cruisin' Off Road xfer case skid) and the cross member using a floor jack.

Off came the 4 bolts holding the locker motor on, break the existing RTV gasket, remove the wiring clip... and oh, look at that... the breather hose was not attached. The hose had rotted and fallen off the nipple. This is where the water got in.

Opened the locker actuator, inside was about 1/4 filled with mud and water. Luckly no metal had started to rust on the gears. Started cleaning it up with brake clean and set the gears to sit in a bucket of CLR.

Where the locker actuator goes into the transfer case...

I noticed the 3 little bronze "tabs" that ride along the top of the gear assembly looked in bad shape, all green and kind of rotted. One of them fell off when I touched it. F**K! Was not happy. Spent half an hour on the tele calling various motor rebuild places and hobby shops, no one had anything even similar to the tabs.

Sitting outside on the ground by the truck brainstorming about cutting out my own from a sheet of bronze or thin metal, when it hit me.... I KEPT THE REAR LOCKER MOTOR THAT I HAD TO REPLACE FOR PARTS!!!!!!!!! Sudden hope!

Ran inside, sorted through the bin of car crap, found the bag of rear locker motor parts... opened the actuator, held my breath...... YES! THERE IT IS! The exact same little piece of triangular black plastic and 3 PERFECT LOOKING tabs. Score. Removed the 2 screws, the silicone, and the rubber grommet holding it in. Set it into the center motor actuator and it was a perfect fit.

In a great mood now, I set to soldering and heat shrinking the 3 wires - Black, green and yellow. Both rear and center motor actuators had the same 3 colours, so I figured it was a no-brainer. Finished cleaning up the rest of the center actuator, installed the tab piece salvaged from the rear locker parts motor with new silicone, greased up the gears and re-assembled the actuator. Plugged it into the truck harness, turned over the key, and pressed the CDL button. The motor moved a bit, then stopped. I pressed the button again... nothing. WTF?? Then noticed the motor on the actuator was getting warm. Crap! Pulled the plug and opened it up to see what had happened.

After some help from my electrical minded friend, we came to the conclusion that the yellow and green wires were reversed... opposite of what the rear locker motor had. Therefore, it never sensed the "end of travel" on the gear, and just kept pushing. Luckily we caught it before any damage occured, and after switching the 2 pins in the connector harness, it tested and worked perfectly

Now, checking the FSM, it states very clearly on re-assembly to

"Set the motor actuator in differential lock condition"

I thought this was odd, since we removed it while unlocked. However, putting my faith in Mr. T, I did as I was told. Re-applied RTV, bolted up motor, attached wire and a new breather hose, went for a drive... you could hear the relay click properly at the beginning and the end of travel, but... the xfer case would not lock.

Back into garage... floor jack underneath... out with 12 bolts, down crossmember... out comes locker motor... now to think. If we took it out unlocked, then putting it back in locked would mean that the gear would turn back further away from being locked, would it not??? Logic told me yes. So I ignored the FSM, installed the motor while in the UNLOCKED position, and tested. Works!

Time for several of these...

 

[asutherland]

Bump... added pictures to my story above.

New question: The sensor for telling when CDL is locked (yellow solid CDL light on dash + ABS Off light) - where exactly is it? I don't recall seeing it when I was in there. This leads up to my next question...

In the last week or so, when I've locked the CDL, the dash light flickers - goes on and off, stays on for a few mins then flicks off, accompanied by the corresponding ABS Off light - repeat. This is controlled by the independent sensor, correct? Is it the same as the front/rear locker sensors? (push ball sensor on 2 wires) The actuator is working as desired, press CDL button, listen to the relay click, the motor wurrr... then click again as it reaches the end of travel.

The truck APPEARS to be CDL locked the whole time, but it's hard to tell when it flicks on and off so much. The only other explanation other than the sensor I can think of is that when we put the motor actuator gears back into the transfer case, there is a bit of play in the gears (on purpose) - is it possible the play was too far one way or the other, causing the CDL to "sort of" lock and just be catching on the edge of being locked?

 

[BlackLS1]

there should be a sensor on the front of the transfer case that senses that

 

[asutherland]

Sooo, update: I went for a test drive in a gravel lot to see if I could determine when the flickering is happening. It turns out it only flickers while it's attempting to lock (after the elec motor has turned and loaded the spring, but before the transfer case is actually locked - while it's attempting to mesh)

Once it's actually locked, it performs as expected and stays solid the whole time. It locks and unlocks normally with no issues.

Thoughts? Non - issue? Before my recent work (this post) on my CDL, when I locked it, the dash would stay dark until it was actually meshed, at which point it would click on solid. Now it flickers while it's meshing.

 

[asutherland]

Sooo, update: I went for a test drive in a gravel lot to see if I could determine when the flickering is happening. It turns out it only flickers while it's attempting to lock (after the elec motor has turned and loaded the spring, but before the transfer case is actually locked - while it's attempting to mesh)

Once it's actually locked, it performs as expected and stays solid the whole time. It locks and unlocks normally with no issues.

Thoughts? Non - issue? Before my recent work (this post) on my CDL, when I locked it, the dash would stay dark until it was actually meshed, at which point it would click on solid. Now it flickers while it's meshing.

Solved it!

So....recently my CDL stopped working, AGAIN. I'd press the button, and no relay noise and no motor attempt... but it was drawing current. I could tell because the interior lights would dim slightly while the button was in.

I took it back out, assuming no water or anything had gotten in.. I was correct. It was clean. So why the issue? Well, inside the main locker motor housing, the gear with spring (for loading) had pushed the spring right overtop of the manual stop point, jamming the gear assembly.

Now, the only way for it to do that (because the electrical end-of-travel contacts SHOULD stop it before it gets that far) is for something on the gear end (in the xfer case) to force it further than it should go.

I stuck my hand into the hole on top of the xfer case, (where the motor bolts to) and felt the small gear inside. It had some give, about 2 inches in either direction. I then locked the xfer case manually by
1. Chocking the front tires
2. Putting xfer case in NEUTRAL
3. Jacking up ONE rear tire into the air
4. Reaching into the xfer case and with my finger, move the gear backwards (towards the rear of the truck) WHILE moving the rear tire with my foot

I knew once it was locked because the gear "slipped" in, and the tire stopped moving. Once locked, the gear had zero play.

This is what was causing my issue (after my initial rebuild). The FSM states to lock the motor when re-assembling, by which they mean lock BOTH the xfer case and motor when re-assembling. This ensures the gear is in the EXACT right position. If you remount the motor when it's unlocked, there's too much slop in the gear.

Now when I lock the CDL, it operates like it used to. Push button, move truck forward about 6 inches, lock light comes on. Same to unlock. No flickering, no intermittent... it locks nice and quickly and without hesitation.

 

[Chalky]

Hi all,

thank for this excellent summary and a good place to start

 

[Chalky]

Wow

I cant wait to get started now and I am ready for anything.

I will keep you posted. I suspect I have all the faults on both Central and rear diff locks.

Car is flood damaged.

 

[asutherland]

Oh man. I remember this bull****!!

For the record, my rebuilt rear locker motor lasted another couple years and started acting up again. Being completely done putting up with its bs, I bought a new one from Akella (on here) and have had zero issues since.

My cdl is still working properly. To be clear on my old post above, they want you to lock the cdl before removing the motor. Fine and dandy if your cdl is functioning. But if it'd not, you have to manually lock it as per my instructions above.

 

[Chalky]

Ok I nee to get them off and apart first.

Just to confirm you recon that that they must be locked before removal?? Surely you are right and if not working there is no option.

I get the pont about locking them before reassembly. Well made by you.

Ta Chalky