If you care about resale value of your printer at all, please don’t do this.
well, there you go 
good answer…
that was supports answer too. and a good one…
however, that port, aux power out mosfet is being used by what appears to be the 5v extruder fan. Not only that , but its labeled 5v… so im not sure how im supposed to use that port anyway
Are you wanting to run a always on 5V fan(hexagon extruder coolling) or a 24 V software controlled fan?
im going to run a 24v always on fan, which i connected directly to the board on the aux/power port with a servo wire. ran that to the hotend.
but realized that STL model that i downloaded stifled the air flow and kicked it back out the front, and didnt cool at all. so im trying another.
and then i realized that one i found was for the layer… so back to searching
Here are the instructions on where to plug the fan bits into a Rambo board that doesn’t already have the wire ran, such as that found on a Taz 3: https://ohai-kit.alephobjects.com/project/taz3-hexagon-toolhead/
Sorry to pull up an old topic, but I need help with a firmware configuration error I’m getting when trying this upgrade. I have a Taz 3 which I upgraded with a hexagon hotend. I’m trying to have a part cooling fan (which I already have working) and a 12 or 24V heat sink fan that I can control or that automatically comes on when hot.
I already ran the wiring as described above and am working on the firmware. I made the edit to configuration_adv as described above, but I get a “‘FAN1_PIN’ was not declared in this scope” error in the temperature.cpp page. I never edited this page and I copied/pasted the code exactly as it appears above. I am using Arduino version 1.0.5-r2. Any help would be appreciated. I can include the exact code if that would be helpful.