Fan pin J13 J14 polarity on v1.4 LimeSDR?

I am trying to identify the polarity (+,-) of the pin headers for the fan (J13, J14). From my study, these 3.3v pin outputs are only active when the LimeSDR reaches a specific temperature, and I would prefer not to heat the board just to determine the proper polarity for the fan. Has anyone determined the fan pin polarity?

Cooling recommendations? check whole, many photos and instructions
Also you can operate fan output manually, through spi commands

It appears the convention on the LimeSDR v1.4 is that square solder pads are ground (-). Therefore, the pin closest to the USB side is negative, and the pin closest to the multi-antenna ports is positive. To activate the fan manually, please see: