Back Chassis Fan is not Running?

It was working earlier and now its not running. But when I start the computer it is running but cuts out later on.

@HelpWithPC:

does it work consistantly if you change where it's connected to power? ie different mobo point, fan controller cable etc.

get some Noctua fans.

Is it connected to the mobo or directly to power/external fan control?

Seems odd for it to initially work only to "get tired of running" unless there's some sort of power management involved.

Open the case up, find a 3 pin header on the board and plug it in. See if that works, if not, then the fan is broken.

There was nothing wrong with it. I check the fan controller and it just wasn't running for some reason cause it was to cool. I changed the setting to run and its doing fine. Also I do plan on getting Noctua fans. It is connected to mobo and the rest are molex except for the cpu fan.