I finished 2 days ago my mendelmax build with a rumba board running with repetier firmware, but now i have a question where i dont find an answer in the net. On the rumba board are 2 pins for fans and fan1 can be controlled nicely from the repetier-host software. Its defined in the pins.h on pin7, pin8 is optional for a second fan and was commented out. So i uncommented it in the pins.h, but how do i start that fan now ?
I want to run 1 fan for cooling the board and the other one is for cooling the printed object as im printing PLA at the moment. The gcode M106s xx is just for fan1 on pin7. And as ive seen there is no gcode for an additional fan.
Do i have to add an custom gcode in the firmware to switch pin8 or what is the best practice to switch additonal pins ?
Or is there an gcode to switch pins directly which i have overseen ?
ok, seems ive found a solution myself: https://github.com/repetier/Repetier-Firmware/issues/16 will test that later when im at home…
and because i like it so much to talk to myself 
M42 P8 Sxxx works perfectly with repetier to control fan2 on pin 8 where xxx is the speed you want to run your fan…
next problem solved