I'm using a MKS mosfet for the bed(but even connecting the heatbed directly to the RAMPS doesn't work either) and using pronterface+marlin.
I have already checked that there is connection between all the components and that I didn't reversed the wires, and as far as I know its the only thing that is not working in the printer; the extruder heats, the motors move and the endstop work except for the heatbed.
What else should I check to locate the problem? I'm definely open to sugestions.