Truck Down! cdl will not dis-engage...need pros.

Discussion in '80-Series Tech' started by cool breeze, May 5, 2008.

  1. CJF


    Oookay; how about some Cliff's Notes?

    What exactly's the issue?

    Oh, and you can drive on pavement with the CDL engaged if you really need to (DD, etc.); you won't hurt anything. (See recent controversial thread on this).

  2. Really, everything ive read so far was against it but must have missed that thread. WHen i did jack up one wheel to verify the tcase was locked the wheel did about half a rev.

    Went wheeling yesterday, now cdl is locked in low AND high
    drove in circles, pavement, grass, forward, reverse, h/l....still locked
    the two related fuses are good
    cdl relay is good.
    cdl is good but doesnt matter becasue my dash hasn;t been in the truck for over a week
    next is to verify cdl actuator motor is bad but not sure if im testing the right harness(see other thread)

    umm, yeah
  3. Ruadhrigh


    could you clarify this?

  4. jonheld


    New Jersey
    Your truck is not "down". Remove one driveshaft and go about your business until you have time to properly diagnose the issue at hand.

    Remove both driveshafts and manually rotate the transfer case output flanges. You will know right away if they are locked together.

    From that position you will easily be able to troubleshoot. Start from the actuator motor and work backwards. If the motor is not getting lock/unlock voltage then the problem lies upstream.

    If it is getting voltage then pull the actuator assembly off the top of the transfer and have at it. There are finger contacts on a rotating gear that are the limit switches (full lock/full unlock) and they can be probematic.

    Follow along in your FSM and EWD.
  5. meant cdl SWITCH
  6. TrickyT

    TrickyT Hate that mud... SILVER Star

    Mill Valley, CA
    You say your CDL relay is "good", but it doesn't appear to pass all the tests to me. (See reply to post in your other thread.)

    You need to do the actuator motor tests suggested in another reply in your other thread.
  7. TrickyT

    TrickyT Hate that mud... SILVER Star

    Mill Valley, CA
    Wait, are you saying you removed your CDL dash switch a week ago, then went wheeling yesterday and your CDL locked when you put the transfer case in 4WD low, and now it won't unlock? If this is true, you need to put the CDL switch back in, turn it off, and shift out of 4wd low. You can't just remove the CDL switch and still have the center diff lock work. For the CDL to function properly without the dash switch, you need to add a jumper between pins 7 and 10 on the switch connector.
    Grolar likes this.
  8. WEll, that's a GREAT thing to know! Guess last time i wheeled i dodn't put it low so this didn't happen and make me think about the cdl button.

    Cliffs: CDL will not function properly without all components attached:bang::idea:

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