Thanks thief for your help 
Bought watches at local REI, all 4 sensors directly from Garmin.
By now I am guessing there is a general hiccup with the 935 software and the pod. Although weird there does not seem to be others with this issue (according to Garmin and a simple google search).
I am pretty technical, I think Yes new batteries, for sure closed correctly, no other riders around etc. I have even tried to leave my running shoes far away to make sure the watch would not get confused with the the footpod and speed sensor both in range.
Thing is you can always get it to work eventually, so every time I get help from Garmin we “think” this is IT, but alas, problem always returns.
I think I just have to give up on it and get a different brand sensor, too many hours lost that could have been used actually training