How to disconnect hot end from wiring harness?

There are a number of instrucionals here in the forum that include the step “disconnect hot end from wiring harness” (see here). But I can’t figure out how to do it on my AO-100. Do I have to cut wires? Or is there something that can be disconnected and reconnected? Can anyone offer any help?

The AO-100 didn’t have the quick disconnects that all the printers from the AO-101 on up had, so you would either need to disconnect it at the RAMPS board end, or cut the wires and crimp on crimp fittings. To use a buddaschnozzle 2.0c on the AO-100 for example, you would want to add 2 4 pin connector blocks, one for the motor wires and one for the heater core and the thermistor. Depending on the age o your machine you might have a 2 pin connector block in the wiring harness somewhere already. You can reuse the pins from that.

The parts you would need for the crimp fittings ordered from digikey are:

housing bodies:
WM2902-ND 0050579404 CONN HOUSING 4POS .100 W/LATCH - At least 2 of these
WM2535-ND 0701070003 CONN HOUSING MALE 4POS .100 - At least 2 of these
and pins and sockets:
1-66360-6-ND 1-66360-6 CONTACT SKT 14-18AWG CRIMP TIN - at least 8 of these (more is recommended in case of crimp error0
1-66361-6-ND 1-66361-6 CONTACT PIN 14-18AWG CRIMP TIN - At least 8 of these

The 2 pin pieces Lulzbot uses for the endstop disconnects are these housings:
WM2900-ND 0050579402 CONN HOUSING 2POS .100 W/LATCH 0 0.45800 $4.58
WM2533-ND 0701070001 CONN HOUSING MALE 2POS .100 0 0.73700 $7.37

The 2 pin pieces use the same crimp pins. You would also find the 4 pin pieces on the 2 Z motors and the Y Motor.

For the 4 pin ones, here is the correct color pinout looking down from the side with the latch. The Male pin section goes on the motor / hotend side of the cable. With the latch side facing you, the hotend collors are red red, orange orange (Does not matter which orange or which red) and the motor side is Red Blue Green then Black.

If you decide to do the rest of the machine the other motor connections should be identical. I’d recommend at least doing the Z motors because it makes them much easier to remove for upgrades. The endstops use the 2 pin connectors and it doesn’t really matter which wire goes where so long as you match the black and the white ones up.

Thanks piercet, that is much appreciated.
Is this the 2 pin connector block you mentioned?:

Yeah, thts the one. There is a splice in the other two wires at that red heat shrink point as well, so thats probably the best point to make the cut anyways

piercet, do you think this tool is good enough to do the crimping? Or would you recommend something higher end?

You will need a dedicated pin crimping tool for those. The stripper tools like that won’t work.

Hi piercet, I have a question if you are about.
I have ordered in the parts you suggested in your post above and am preparing to do the changeover.
The budaschnozzle 2.0c came with a 4 pin connector already attached. It says on the budaschnozzle 2.0c spec page that the male connector pins are 24-30 AWG. Will these be compatible with the 14-18 AWG female pins you listed in your post above? Or is it better to cut off that connector and crimp on a new one using the pins I ordered in from digikey?

Not sure. I thought mine were the same size. Try a test fit first and see if they look right before you cut anything

I tried one of the female sockets I ordered in on one of the male pins in the budaschnozzle connector and it feels loose. Much looser than if I try the female socket on one of the male pins I ordered in. I think I’m just gonna order in a dozen each of the pins listed on the budaschnozzle spec page and put the job of until next weekend. I felt more like drinking a few beers today anyway :smiley: . I could cut the connector of and crimp on the pins I have but then I would have to do the same thing in the future if I want to upgrade again. I can use the pins I have for crimping practice. Looks like the stepper motor uses smaller wiring too, 22 AWG.

Sound like a plan piercet, or should I go ahead with the larger crimp pins I have?

That should work!

I’ve finished this project now and just want to leave a few notes in case anyone else looking for help finds this thread.

After the last post I made I took a closer look at what Lulzbot sent me with Budaschnozzle 2.0c. It turns out they had already sent me everything I need to make the hot end disconnectable and no extra crimping was required. They had sent wiring to connect at the RAMPs board for the heater core and thermistor and a 4 pin connector at the other end to plug in the connector on the Budaschnozzle. It was very easy to connect the wires at the RAMPS board; there was a 2 pin connector for the thermistor wires and the heater core wires are just inserted into a hole and then a screw is tightened to clamp them down for a good connection. The most work was probably just removing the black spiralling wire cover that routes the wires, and that wasn’t too bad.

For the stepper motor I did go ahead and cut it’s wires and crimped on the 2 4 pin disconnects. If you are planning to the same it’s important to note that the housing bodies piercet called up in his earlier post are correct, but the pins and sockets are not. They will not even fit in the housing bodies. The pins I used from Digi-key were part numbers:
WM2510CT-ND for the female pins
WM2517CT-ND for the male pins

I used HT-225D crimping tool which I ordered on Amazon. I saw it recommended in the forums here and it worked fine. I hadn’t done any crimping before. If you haven’t either I recommend doing some research on Google & youtube, it’s very helpful. Check out this guide from Molex, it has pictures of what good crimps and bad crimps look llike. If you don’t have a magnifying lamp I recommend getting one because the crimps are very small and a magnifying lamp makes it much easier to see what you are doing.

After reassembling the hot end to the printer I leveled the bed and did a print. It was a z-axis acme coupler because I had broken one when I was trying to figure out why my old hot end wasn’t working anymore. I managed to glue it back together with acetone to make the printer functional again. The new one printed out like a dream with the new hot end.

Thanks piercet for getting me on the right path with this project.

There is a rubber connector that goes from the bumper into the trunk. You can disconnect the bumper wiring from inside the trunk by prying the approx. 2-inch diameter rubber grommet out of it’s hole in the trunk sheet metal, then you can disconnect the socket.