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Center Diff Lock Light?

Discussion in '80-Series Tech' started by ek1029, Apr 21, 2003.

  1. ek1029

    ek1029

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    When I'm in Low on an 80 series TLC is the center diff lock light supposed to be on? Doing a little wheeling this weekend when I shifted into low to get some traction again, I didn't notice the light, but did notice the traction.

    Thanks
     
  2. Beowulf

    Beowulf

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    Ek1029,

    The following assumes a stock FZJ80. (i.e. No CDL switch)

    The center diff lock light should blink when you put the tranny in neutral, the transfer case in low range, then put the tranny in gear. When the xfer case signals the ECU that it is locked, the center diff lock light will stay on solid. The ABS light will come on if your truck is equipped with ABS. This indicates ABS is disabled.

    You didn't say what year your truck is. I believe the locking and the light works a little differently with FJ80's (91-92)

    -B-
     
  3. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    ek, (what should we call you?)

    If you have a US spec 80 with full time 4wd AND you have not done anything to any wiring, the center diff should lock when you shift into low range and a light should come on in the I.P. to indicate that you are locked. If it felt like it locked up you could have a burned out indicator bulb. Some further testing needs to be done to see if it is locking or not.

    Regards..........Dan :beer:
     
  4. ek1029

    ek1029

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    It's a 93  (stock, ie no center diff switch installed).   I'm not seeing any center diff lights or ABS lights... Hopefully it's just burned out, but what would be a good way to test it?   I would guess it was locked this weekend, but like I said maybe it was just the low gearing and the capabilities of this truck w/out even being locked in 4wd low fooling me.  

    Thanks,
    Erik
     
  5. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    Erik,
    It is not likely that both the ABS and the CDL bulbs would go at once. A quick and dirty way to see if it's locking is to go to a paved parking lot and drive in a tight circle, stop and shift into low and do it again. If the diff is locking, the vehicle should feel like it's binding up in the turn, if it feels like it did in high(other than speed in any given gear) you got yourself "no lockey diff". Then it's time to trouble shoot.

    Regards..........Dan :beer:
     
  6. ek1029

    ek1029

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    I just went down and when I turn the key I do see that the ABS light is working. When I shift into neutral, absolutely nothing happens. I would assume that all of the dash lights would be on the same wiring harness? I say this because I had a stereo put in and they forgot to connect the wiring harnesses and I had to go in and reconnect them, but I'm pretty sure I got them all.

    Erik
     
  7. Beowulf

    Beowulf

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    Erik,
    It would be good for you to know, one way or the other, if your truck has ABS. It was an option in 93; not standard equipment. &nbsp:Does your truck have rear disk brakes? If no, then you don't have ABS. If yes.... I'll have to defer to CruiserDan or another '93 owner. I would guess yes, but they would know for sure. Anyone??

    It is likely that you wouldn't be able to tell if the center diff was locked if you haven't taken it off road and have not used low range before.

    Post back if you want assistance trouble shooting this problem. Expect to be requested to do some work (e.g. using a multimeter, putting the truck on jack stands, opening the dash, etc.)

    Oh, and welcome to the 80s section on ih8mud.

    -B-
     
  8. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    Erik,
    The CDL indicator does not light up when the key is turned to "on" with the engine off, so that is normal. Go back to the vehicle and try this: Key to "on" with the engine off. Shift into low and see if you hear a "click" coming from the LH kick panel or footwell area. That will tell if the relay is firing. If not I would move on to the low 4 position indicator switch on the transfer case. It may be faulty or unpluged. If that's Ok I guess you could sell it to me............. :dunno:

    :beer:
     
  9. ek1029

    ek1029

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    I just drove in a circle and when I tried if after shifting into low I didn't really notice much difference other than being in a lower gear.. It didn't seem like I was skidding a tire at all or anything during the turn.

    YES, it does have rear disk brakes.. It's pretty loaded so I'd guess it has ABS, but I'm not positive. When I start the truck the ABS light stays on for a sec or two then turns off.

    For a little bit of background, my TLC has 170k and I doubt the previous owner (1st owner) ever used 4wd Low. It had a transmission service about 1 month ago if that makes any difference at all.

    I have taken it off road once :) (only had it for a few weeks), but I'm not really knowledgeable enough to really realize if it was locked or not I guess.

    Maybe some of this helps- Thanks for all of your help

    Erik
     
  10. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    Erik,
     Yes you have ABS.

       It may be that the actuator is stuck from lacko use.


    Hey Pair O dice....What thinks ye about this?
     
  11. ek1029

    ek1029

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    Well when I shift into low w/ the key "on" and engine off, I hear absolutely nothing. Where exactly would I find low 4 position indicator on the xfer case? thanks :)



     The CDL indicator does not light up when the key is turned to "on" with the engine off, so that is normal. Go back to the vehicle and try this: Key to "on" with the engine off. Shift into low and see if you hear a "click" coming from the LH kick panel or footwell area. That will tell if the relay is firing. If not I would move on to the low 4 position indicator switch on the transfer case. It may be faulty or unpluged. If that's Ok I guess you could sell it to me............. :dunno:
     
  12. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    Erik,

    This is hard to describe. It's at the upper rear of the transfercase to the right of vehicle center. It has a two wire plug connected to it. One wire is black with a blue tracer the other is Yellow. There is another switch close by with different color wires. I get them mixed up. The wire colors are the giveaway for me.

    Dan
     
  13. ParadiseCruiser

    ParadiseCruiser

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    Greetings Erik, and welcome!

      Based upon your remarks, it sounds to me like the diff actuator is stuck, as Dan has already suggested. There is the actuator indicator switch down there as well to consider... which can mimic this problem, especialy since you are new to the truck and one can seem like the other if you are unfamiliar with the feel of a locked diff.

    But, you should be able to hear the actuator when shifting to low range on the transfer case [key on, engine off]. A stuck actuator is not at all uncommon on trucks where low range has not been used regularly.

     You are in good hands with Dan here - sounds like he is right on top of things (as usual)  ;)

     Cheers !

     R -
     
  14. ek1029

    ek1029

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    OK... GOOD NEWS!!!

    Well I crawled around under the truck for a few minutes w/ the flashlight and looked for anything noticably weird.  I found that one of the plugs on the transfer case wasn't plugged in!, so I plugged the sucker in and started the car.  I shifted into neutral ,didn't see lights, then I shifted into low and about a second later the abs and diff lock light lit up.

    So, I guess it was never locked last weekend when I thought -I was getting stuck and switched into low to get out of it.  I can't wait to see the difference next time I go up, if I can even find anywhere to really get stuck :).  I can't even imagine the traction  everybody w/ lockers in the rear & front differentials must get.

    Thanks Cruiserdan and Beowulf and everybody else for the help...

    -ERIK
    Claremont,CA
     
  15. Beowulf

    Beowulf

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    Erik,

    Dan's the MAN!

    The center diff, when locked, transfers torque 50/50, front/rear. While this will help in some low traction situations it isn't as dramatic as low range and the factory diff lock option (or ARB lockers.) Most people believe the center diff transfers torque 30/70 front/rear under normal conditions. I haven't seen this torque split in print from Toyota though.

    The CDL switch has been discussed recently on this forum. Do a search if you are interested in adding this accessory. The OEM switch is available from Slee off-road. CruiserDan posted a mod to the wiring that enables the switch and retains the transmission shift pattern that is matched to the Low range.

    -B-