My new XPS 15 9560's fan are always on when connect to the external monitor using the USB C port. While searching for the issue online, I found many people saying having similar issues - either connect using a USB C dock or any USB C adapter.
I also have checked the temperatures of the CPU, it's in mid 30s, not high. the temperature of the PCH jumps to 50C from 35C when I connect to the USB C port.. I wonder it must the PCH causing the issue?
Thanks for posting.
Have you tried running systems diagostics either from F12 at startup or from Dell Support Assist.
From reading on NotebookReview, the hypothesized issue is that the Thunderbolt controller activates any time something is connected to the USB-C port, even if it's not a Thunderbolt device, and the Thunderbolt controller itself consumes a fair amount of power and therefore would generate a fair amount of heat. Not sure WHY this has to (or at least does) happen, though.
Everything passed OK.. Am I supposed to see anything particular? this problem has existed since the 9550 days, when it's connected to the Dell docking station..
Since everything passed, you may wish to give Tech Support a call for additional troubleshooting.
You can contact Tech Support at 1-800-624-9896 or 1-800-288-4410, or you can initiate a chat session http://dell.to/2v4snVm