DIFF LOCK Light ON!! Cant turn it OFF!!! HELP!!!!

[Tools R Us]

Not sure about the FJ80, but on mine the differential lock relay / transmission relay are one and the same, it says transmission relay on it, but is sometimes referred to as the differential lock relay, as that's the function it serves.

 

[FloridaFJ80]

yeah i have the same thing.. when i take off the front drive shaft do i need to disconnect anything else. or is like a plug and play thing?

 

[e9999]

(edit, forget this, thought of front diff: if your diff is locked, removing the DS is not going to eliminate the stresses on the axles and Birfs when you turn.)



How about you open up the diff lock actuator, and see if the actuator is stuck and can be pulled out manually?

I, personally, would not drive 1 mile on pavement with the diff locked...

 

[Tools R Us]

if your diff is locked, removing the DS is not going to eliminate the stresses on the axles and Birfs when you turn.

How about you open up the diff lock actuator, and see if the actuator is stuck and can be pulled out manually?

A '92 FJ80 doesn't have axle lockers, so I doubt his axles are locked!

 

[e9999]

A '92 FJ80 doesn't have axle lockers, so I doubt his axles are locked!

aw shucks... OK, that was just a Freudian slip, I'm fixated on front lockers, I guess....

 

[photogod]

Have you tried to remove the motor actuator? Kinda tough to get at but you could remove that and check it for proper function. The control relay is in the driver side kick pannel. Check for continuity between terminals 1-2, 2-4, 6-7. There is a diod between 6-7 so if the circut shows no cont you may have to change the + & - and recheck the circut. The wire harness side hsa two rows starting from top right and going left is#1, 2, 3, 4 then to the bottom right going to the left is 5, 6, 7, there is no 8 empty slot, then 9, 10. Good luck!

P.S. There is more to test the relay side but I can't really explain it. If you send me your email I will scan the FSM pg TF-50 and send it to you. firstlightphoto@mn.rr.com

Tim

 

[CJF]

Why not just remove your front driveshaft, and see if you are locked.

Good call. Should be done before any more miles are driven on it.

Florida,

No, there is nothing else you need to do for this band aid/temporary fix. As long as you're indeed locked, when you remove the front DS it will act like a run of the mill rear wheel drive 2wd vehicle.

Curtis

 

[FloridaFJ80]

I will try to find my Ohm meter to test everything and hopefully i will be able to troubleshoot the system that way.. I found that sheet in my FSM. I appreciate you willing to scan the page for me..

So disconnecting my front driveshaft should temporarily take that noise away??

 

[FloridaFJ80]

Thanks so much for the input everyone.. i will take out my front drive shaft tommorow while i troubleshoot this further.

 

[fj803fe]

I will try to find my Ohm meter to test everything and hopefully i will be able to troubleshoot the system that way.. I found that sheet in my FSM. I appreciate you willing to scan the page for me..

So disconnecting my front driveshaft should temporarily take that noise away??

It may not totally get rid of the clunking noise in a hard turn.

I guess we are all on the "its definitely locked" thing here, but....

...how hard is it to go to a full turn-are you only hearing the clacking noise? If you hear a definite "chirp" (i.e. tire screeching across pavement to realign itself) you could be locked, but on gravel, dirty pavemet, etc. You can get the sliding, sound of 4-wheel drive, etc, sound. I would be interested to hear how "HARD" it is to turn the wheel or moreover do you have trouble getting to full lock/turn when moving relatively slow????

The light thing is a pretty good indicator something is up-just want to have yourself make SURE.

In response to this, now that the switches have been replaced and the light is on-how far have you driven it with the CDL switch "off" (i.e. Have you, since replacing the said switches, driven any distance to see if the light will switch off after turning "off" the CDL switch)? It can sometimes take a while and I have thought mine may have a problem as I would drive for some time and the light would be on-I will fiddle with the switch a couple of times and try comming to a stop, going forward/backward, etc...

You could remove the DS and have that same "clacking" noise-just to prepare you-it could be your birfs and not associated with the center differential. Not necessarily a sign that they are "bad" (i.e. not driveable) but wearing/making noise. A re-pack may not reverse this situation.

I recommend you familiarize yourself with this; however. It is clearly written up in the FSM and I would do a search for Birfield or Birfield Repack.

 

[FloridaFJ80]

fj803fe - When I make tight turns, for example to pull into a parking spot, my rig slows to a crawl unless i give it gas, the noise starts when I am making that tight turn along with my tires squelling. So i am pretty sure that my rig is locked.. Since i replaced the switches, i have driven about 60 miles, with my DIFF LOCK light on. And still it is locked.. I havent taken my driveshaft off yet but i will be doing it within the next day. I am hoping that my birfs arent broken but i am preparing myself for it. I am going to look at my FSM and try to find out on how to repack my Birfs.. But i really want to fix my locked differential before i buy new birfs.... gonna be calling CDAN soon to get some parts after i do the OHM meter testing..

 

[Darwood]

Taking the front drive shaft will also confirm that the cdl is engaged. If you take the shaft off and you can still drive the truck then it's locked. If you take the shaft off and the truck doesn't go anywhere then it's unlocked.

 

[Rich]

I guess its already been said, but it bears repitition that if you are driving on the street with center diff locked you are likely trashing your driveline. Bad news.

 

[Super Cruiser]

Before doing anything like removing the front driveshaft, you should remove the fuse that powers the difflock ECU. This should re-set the ECU. Replace the fuse and try again to cycle the diff lock switch and or transfer case shift lever. If this does not work post a response and we can try another trick.

 

[fj803fe]

Before doing anything like removing the front driveshaft, you should remove the fuse that powers the difflock ECU. This should re-set the ECU. Replace the fuse and try again to cycle the diff lock switch and or transfer case shift lever. If this does not work post a response and we can try another trick.

Good idea, I second.

fj803fe - When I make tight turns, for example to pull into a parking spot, my rig slows to a crawl unless i give it gas, the noise starts when I am making that tight turn along with my tires squelling. So i am pretty sure that my rig is locked.. Since i replaced the switches, i have driven about 60 miles, with my DIFF LOCK light on. And still it is locked.. I havent taken my driveshaft off yet but i will be doing it within the next day. I am hoping that my birfs arent broken but i am preparing myself for it. I am going to look at my FSM and try to find out on how to repack my Birfs.. But i really want to fix my locked differential before i buy new birfs.... gonna be calling CDAN soon to get some parts after i do the OHM meter testing..

yeah, just wanted to confirm, and also say (though do the above first-I think) or otherwise prepare you that the "clunking" of the birfs is often a seperate animal than the center diff and may still occur w/ center diff unlocked/DS off.

But DS off or above Fuse reset should result in a reduction of that noise and less strain/"hardness" in turns.

 

[FloridaFJ80]

Where is this fuse Located???I have searched for it on the truck any ideas whats it named under??? I have been so frustrated with this problem that i havent touched my truck in a few days. I want to fix it as soon as i can..

 

[FloridaFJ80]

Well I went ahead a nd looked at my FSM and found the fuse its a 30A located in the Fuse block under DIFF. I pulled it out it wasnt shorted it was still good. I went to the Transmission relay and looked at it and no contacts or anything was blown or anything, looked brand new. I put the fuse back plugged back in my relay and tried again, put it reverse then drive, put the CDL switch on and off. repeated this a few times, put the car in LO and tried again. Defientely felt different from HI to LO in the D position. The engine would rev a little more and the truck would move a lot less. Is that normal?? I am thinking its a bad motor actuaotr, but i still havent done the OHM meter tests yet... Anybosy else have any more ideas...@???

 

[CJF]

Anybosy else have any more ideas...@???

Please tell me that you've either jacked up the vehicle or removed the front DS to absolutely, positively verify that you/we are dealing with a locked center diff.

Curtis

 

[Beowulf]

FloridaFJ80,

You need to follow the advice given by Curtis (and others) to remove the front driveshaft (aka propeller shaft.) Instructions are in your FSM. Be sure to mark the flanges so that you can reinstall it exactly like it was before removal.

After removing the DS, your truck should not exhibit the symptoms you are describing. If it does, then you have a bad birfield or possibly a bad flange. A bad flange is fairly common and an easy fix. They are also reasonably priced. A bad birfield is more $$ and a more difficult repair. Either of these conditions means you need to stop driving the vehicle and get it repaired ASAP.

If your symptoms go away, then you have a problem with the center diff; probably with the actuator. You can continue to drive the vehicle in 2WD and get it repaired after you isolate the problem.

Your next post in this thread better be after you have done the suggested test. Otherwise, everyone is going to give up on you and tag you as a troll.

-B-

 

[alkaline747trio]

Well said Beo. I was personally waiting for him to do something before posting again, seems like he doesn't wanna get his hands dirty. Poor Floridian...guess they are ALL, even the LC owners, poor drivers just kidding of course.