Different wiring of the relays removes risk of shorting the power supply, so no need for diodes to motor, but I added a resistance of 8 Ohms as additional security (in case the motor decides to short internally, probably not necessary).Also, there are no capacitors, because they might influence reaction speed of relays.I did the schematics with "fritzing", somehow they don't look as fancy and understandable as other schematics seen around here. What software do you use to draw schematics (on a mac) ?This absolutely solved the erratic bahaviour of the DC Extruder Motor, who is now ready to print correctly the parts for a stepper extruder. :-)Oh and yes, if you build this and the motor spins backward instead of forward, just invert the cables which go to the motor. :-)