Mendel90 & e3d fans failing

Hi

Today, I attached the cooling fan to the extruder. Before that I already had the small hotend cooler constantly running on 12V. I used to connect the hotend fan through the fan- and the spare cable. The spare cable was connected to the 12V AUX of my RAMPS 1.4. And FAN- to AUX GND.

Now, I had to reconfigure the cabling. The hotend fan connects now to +12V on (Pin 10, 3 & 11 on the D type connector) and the spare cable to AUX GND on RAMPS. The extruder fan connects also to +12V and to D9- port on RAMPS.

The hotend fan runs constantly 100% and the extruder fan is controllable as it should be, unless I switch on the extruder heater... Both fans comes to halt until the temperature set is reached. As if the heater is consuming all the power letting nothing over for the fans.

Did I do something wrong, or is it because of RAMPS? Do I have to pull dedicated powerlines for the fans?

I think you must have the heater wires swapped at the RAMPS so pin 3,10 and 11 is actually hotend-. When the heater is off that will be +12V via the heater resistance and the fans will run. When it turns on it is grounded so the fans turn off.

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Thank you Nophead!

The heater + and gnd were indeed swapped...

Shame on me