Thanks for posting. Apologies that your system is not working as expected. Please perform a systems diagnostics by pressing F12 at startup or by running Dell Support Assist.
The fan will run at optimized performance automatically when there is a change in temperature & when it reaches a set temperature. If the fan is still not running you could update the bios from this link http://dell.to/2ueCzpY
I've had this same problem since I bought my 7567 last year, I've updated bios I'm on 1.8.1. all my drivers are up to date. could this be as simple as a loose connector? Is the fan just bad? I've seen a lot of reference to this issue around the internet. Is there a known solution?
Did you run the diagnostics on the fan? Click the link below for troubleshooting fan issues.
For my notes, click my username and send me the pc service tag number via private message.