Z270 extreme 4 fan control issue

graysil wrote: Just setup a new Z270 extreme 4 and have a weird issue.  I have a cooler master pro 5.  2 chasis fans and the CPU fan are tunable without an issue.   When I try to tune my CHASSIS 3 fan it aways runs at full speed.   All the chasis fans are 3 pins, but like I said 2 fans are tunable, but anything in the 3rd spot is not (I've tried switching fans around and it still will not work). Its not loud or anything, but I would like to get it to work and have all of them be tunable. Does anyone have any suggestions/advice?

The Chassis Fan3 header must be configured depending upon its use, in the H/W Monitor screen, UEFI/BIOS Advanced mode. There are two options that must be configured.

The CHA_FAN3 header can be used as a water pump header for an AIO liquid cooler, that runs at full speed all the time. You must configure the CHA_FAN3 / W_Pump Switch option, setting it to CHA_FAN3.

Next, you must set the Chassis Fan 3 Control Mode option to either PWM or DC mode. Since the fan on that header is a three pin fan, set it to DC mode, if it was a four pin PWM fan, set it to PWM.

After that, you use the Chassis Fan 3 Temp Source option to select which temperature source is monitored to change the fan's speed. Then select a fan speed profile with the Chassis Fan 3 Setting
option, or create your own custom fan speed vs temperature profile.

You can tune this fan header to your liking, but it has more manual tuning capabilities than the other chassis fan headers, so a little more work is involved getting it to work as you need it.