Wlan wont work on my YUN if 5v supplied to vin

help me. im curious :o it works when i use micro usb .

if i use 3s lipo to power pololu Simple High-Power Motor Controller 18v15 and bec 5v to vin it wont work .

but if i power the pololu with usb and use the 5v bec to vin ...it works .

are the pololu Simple High-Power Motor Controller 18v15 ...yust crap ?? they are sooo expensiv!!!

so now im use a cheap 5v bec from hobbyking and it works . i think the pololu make bad 5v 5v are not = 5v If I had an oscilloscope i would see it now i can use 3s lipo to power my bec and this to power the yun

What connector pins on this controller are you using to try to power the Yun?