It will help immensely if you posted your GPU card Make & Model.
Most modern GPU cards have ZERO RPM Feature. This means that the fans won't turn on until the GPU card reaches a certain temperature ~55c to 60C
Make sure you have all the PSU PCIe Power cables connected to the GPU card's Power ports if applicable.
If the fans don't turn on while gaming or under stress then you have a problem. Under heavy loads the GPU temperature should go over 60C easily thus the fans should be running by that time.
Does the fans turn on for about a second or two when you first power up and then turn off?
If you want to open an Online AMD Support ticket here is the link: https://www.amd.com/en/support/contact-email-form
