Wiring of Ramps1.4

I want to add a Fan.
Generally I have problems to understand the link between the fields inside the configurator of Repetier und the Ramps 1.4 board.

1.In Repetier Configurator
Fan Pin: "Heater 2 normally used for extruder 1" -- is this D9?

2. I want to use the (+) for the fan of D9.
and (-) of the GND of the auxiliary connector 12V "12V Aux" (I think it is described D2).
Is that ok? (I want save one cable..)
(or do have to use the (-) of D9)

3. For Z-Probe I have to define a pin in repetier firmware.
Is the "Digital Pin 1" in the configurator the D1 in the AUX-1 block on board?
Or what pin should I use?

Any help is welcome .. Thanks!

Can't help you with 1 or 3 as I'm not familar with Repetier, but for #2, you could, but it would be unconventional. You also may not get the desired operation. The + terminals of D8-D10 are always hot as long as your power supply is on. They are never switched. Instead, the MOSFETs associated with those connections are NPN, switching the negative connection. Wiring as you indicate would result in the fan always running even if D9 was not turned on. If you want to be able to control a fan via D9, you'll have to use the - of D9. Doing so will also mean that you won't be able to cool the hot end when the hot end isn't on, such as after the print. This usually isn't desired as the fan will normally need to run for at least a short while or the heat can creep up into the hot end causing a jamb. If you need an additional fan control, there are several fan adapters commercially available (search for "RRD Fan Extender" for example) or Thingiverse has multiple designs for one or more fan (or other general purpose) extenders. I used a variation of this design for both my e3D hot end cooling fan and LED lighting.

Also, the 12V aux connection you are describing as D2 isn't D2. D1 and D2 are identifying diodes, D2 is used in the reverse supply wiring protection. D1 is used in powering the Arduino from the 12V connection and you'll often see it talked about being removed when powering the RAMPS with more than 12V or other "alternative" wiring designs.

Thanks for your input!
I have a cooling - always running - fan the hotend.
This is a second fan cooling the part itself. It is controlled with the repetier software.
So I can wire it with (-) of D9 and (+) from Aux 12V,
So it can be controlled, separately from the hotend cooler.
Is this correct?

For 1. and 3. I will go to the repetier forum ... maybe that is the second source !
Thanks

Quote
Georg99
So I can wire it with (-) of D9 and (+) from Aux 12V,
So it can be controlled, separately from the hotend cooler.

If you wire the - through D9, then anything else that is connected to D9 will need to be on in order to turn your parts cooling fan. Typically for a cooling fan on an extruder, it would be hooked up to an always on source, either the 12V Aux connector, or straight to the power supply. The parts cooler is then hooked up to D9 + and - connections.

I don't know if Repetier supports it, but Marlin supports having an additional fan on an unused pin that automatically turns on or off at a given temperature (e.g. 50 degrees C in my case) so that your fan isn't running unnecessarily. But you'd have to have a fan extender of some type to do that. If you don't mind the fan running whenever the power is applied, I'd just wire the always on fan to a always on 12V source, and the parts cooling fan with D9 normally.