I connected two buttons via X12. These work perfectly, both upper and lower. However, I cant get the X11 ports to work. I am trying to connect a DIY handbrake which has a potentiometer. I followed the wiring guide, but it does not work. I checked with a multimeter all the pins on both X11 ports but I cant get a signal through any of them. Is there a step I am missing, to enable analog signals, or what should I check?