Trouble with PC fan turning on when PC is shut down

[David7310]

I have a Lenovo x315 FX
AMD FX-Series FX-770K (3.50GHz)
• 8 GB DDR3 1 TB HDD 128 GB SSD
• Windows 8.1 64-Bit
• AMD Radeon R9 360 2GB
For some reason when I shutdown the PC the fan will kick on at a high rpm at some random time? The monitor will still show that the PC is not giving a signal but the LEDs are light up on the PC and the fan is running high. Any suggestions? Thanks
David

 

[Exeonx]

My first bet is your Power supply malfunctioning, if your PC is shut down there should be no reason any fan turns on.

 

[David7310]

Ok how would I check that its not malfunctioning?

 

[dudeman509]

Honestly, that sounds like a motherboard issue.

 

[Exeonx]

To be honest here, this is kinda hard to check without trying a new component, it's kinda hard to tell you to either buy a new Mobo or buy a new PSU, I've seen this problem before and it can be either.

 

[David7310]

Well thank you, its weird how it runs perfectly fine when in use.