You need a monitor or a dummy plug in the card plugged in the primary PCI-E x16 slot for the drivers to be able to read and set the fan and temperature settings. You also need to change the primary video to the PCI-E slot and not the on board video in the motherboard Bios.
Note: this all worked the very first time I set it up. Not both a Xubuntu with AMDPRO and a clean Ubuntu with stock drivers cause the same issue, both on same mobo.
Now I remember why I was using IGD. Booting to PEG with the monitor plugged into the GPU causes the system to never fully boot (wifi dongle never lights up, wired ethernet never connects) and lands on a totally distorted half black screen.
ALSO the fans on the GPU in the primary slot come to a stop.
This is what caused me to reinstall the OS, but it's never fixed it. Man alive.
AND I just tried on a clean Ubuntu install and the same thing happens. What the heck??