Can't set up flaperons?

Trying to set up flaperons. First I looked into use ‘plane’ set up but I am using 5 of my 6 channel pixracer. [ I was surprised I couldn’t use ch1 and 5 only 5and6?? ] So next I tried setting it up in openTX on my Taranis. After not having any luck for a long time I’m wondering now if I have an issue with my pixracer. I can clearly see in the radio calibration page ch5 moves as it should when I operate the ailerons and flaps… however there is never any output from ch5 ?? The servo never moves. I’ve tried setting ch5 option to both 0 disabled and 1 RC pass through. Neither works… Still no output on ch5… anybody have any ideas?? thx