Welcome to the forums, newcomer!
If all the fans have gone dim, then it's possible that the controller that it's hooked up to has ended up being faulty or is failing. You could try and disconnect other hardware from your PSU that requires power to see if that alleviates the issue.
Speaking of which, what are the specs to your build? List them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS: