GRBL Error: Homing Failed

hello all.
so i got my xxl cutter with z-plus set up and all went well. ran the marker shapeoko logo file with no issues. opened up a new file to send it to the cutter to get the feel for setting up and running a new job. and now in the carbide motion software, after i try to “initialize machine” the z-plus advances the carrier to the top and then chatters. i get a “GRBL Error: Homing Failed, couldn’t find limit switch”. the limit switches appear to be magnetic, so i don’t know how to “hold” them. i cant get the machine to initialize since it wont get past the z-axis limit switch issue. is there anything i can try to get past this? i’ve checked and rechecked the wires and connections and all looks well. and like i said, its been through the initializing process a few times and has been successful. not sure what happened.

and help is appreciated.

They’re inductive… You can hold a piece of metal close to test.
You’re Z switch is not working if that happens. Triple check the wiring.
Does the LED on the switch light when you test?

thanks neil… do the LEDs light when metal is placed next to them?

nope. none of them do. should they light if i cant through the initialization?

Can you check that the switch PCB is seated properly?
Do you see LEDs in the board, near the switch input?

They should work as long as the board is powered and they’re wired correctly.

i guess i lied neil… both the x and the y will light when i put the collet wrench near the end of them. the z switch will not. i checked that the board was seated securely. and to test the board, i switched the x and z cable on the the board and got the same results (both x and y switches lighted). so i think that means the z switch is bad??

added note: its tough to trace the wires sine the colors in the wire harness and the switch leads are different colors.

I hope not. If you switch the X and Z switch at the board, does the problem persist? (Just test with the wrench)

Edit: just read that you already tested that, but I’m confused on the result. The issue moves with the switch? Or stays on the Z input?

yep. i switched the switch cables at the board. tested with the wrench and got the same results (the LED did not illuminate for the Z-switch).

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The led on the board or the switch?

both. neither the switch nor the board would light when the switch should limit (with the wrench placed near it). didn’t seem to matter if the z-switch was plugged into the z placement on the board, or if it was plugged into the x placement on the board.

I know the wire coloring is tough to track, but can you see if it’s consistent for all three switches?

Sounds like either a bad switch or bad extension. We can send you a replacement. Send and email to

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both the x and y axis switches are Black, Brown,Blue, but for some reason the z axis is Black, Red, Green. it seems consistent for the 3 switches. the black wires match, plug for plug.

Maybe a bad crimp in the extension cable? As @rolie said, they’ll fix you up.
Just me or does that blue connector look like ours coming out of the housing in that second pic? If so, try reinserting that connection.

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ive plugged and unplugged them multiple times. no change. kind of odd that it went through the initialization process at least twice and then failed. but electronics can be like that i guess. i will send an email with a link to this thread in hopes of getting it resolved. i will play with the wiring in hopes of better results until a new switch arrives. thank you to both neilferreri and rolie for the help. i appreciate you both.


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Good luck. If you have a meter, check for continuity on each line of that extension.

I do neil… I’ll check it tomorrow and post results. Thanks again man.

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