Thanks adapt for your help!
i am also checking some where else like this site to teach how to use an extra LED to give always on flashing according the speed, however it is only suggest for single speed knob, here is the site :
http://bounav.free.fr/wp/?p=254In our case (2 speed knobs), if i would like the bi-colour led be flashed according to the rate (always on and different colors to indicate which speed knob is using), i suppose the common anode of bi-colour led should be connected to J3 with a 15k resistor and the 2 cathodes go to 10 and 12 of the 4pdt, is that correct?
And for wire 11 to ground, may i know where i connected should it to so that 11 is grounded?
Sorry that my basic concept is so weak, once again thanks for the help in advance!