Confused about mechanical endstops

So simple that I am stumped!
My brain is not working. I have been trying to impliment auto bed leveling but the G29 code never executes anything other than "OK". My theory is it has to do with the endstops not communicating properly. Can someone let me know if the following is normal after an M119 command:
With the bed homed x=H  y=L  z=H
With the bed away from all stops x=  L  y=L  z=L
Why would all change except the y stop? The limit switch checks out fine.
Could there be another reason why G29 does nothing??
Thanks for a reply. Been working on this for a couple of days. Running the latest Marlin FW.
(Actually, another curious observation: I don't see the light respond on the Melzi board during an upload, but the IDE goes from "uploading" to "upload done")

Comments

  • Hello nkuck,

    as you can see - your y-endstop is not changing his state.

    y=L means that your y-endstop is closed to the Melzi Board Ground connection.
    It should change his state to y=H when you "move the Bed".
    If not - something is wrong with this switch or the connection to the board is not
    working properly.
    And your theory is right ;-) You should measure the switch with a multimeter and i am sure
    you will find the bug...

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