# Ubuntu – How to see all the fans in sensors

I use Ubuntu 18.04.2, I installed lm-sensors and what it gives when I command sensors in the terminal:

(base) avy@avy-Moi:~$sensors asus-isa-0000 Adapter: ISA adapter cpu_fan: 0 RPM acpitz-virtual-0 Adapter: Virtual device temp1: +27.8°C (crit = +119.0°C) nouveau-pci-0100 Adapter: PCI adapter fan1: 0 RPM temp1: +35.0°C (high = +95.0°C, hyst = +3.0°C) (crit = +105.0°C, hyst = +5.0°C) (emerg = +135.0°C, hyst = +5.0°C) coretemp-isa-0000 Adapter: ISA adapter Package id 0: +27.0°C (high = +82.0°C, crit = +100.0°C) Core 0: +26.0°C (high = +82.0°C, crit = +100.0°C) Core 1: +26.0°C (high = +82.0°C, crit = +100.0°C) Core 2: +27.0°C (high = +82.0°C, crit = +100.0°C) Core 3: +27.0°C (high = +82.0°C, crit = +100.0°C) Core 4: +25.0°C (high = +82.0°C, crit = +100.0°C) Core 5: +27.0°C (high = +82.0°C, crit = +100.0°C)  But my fans are not appearing, and I have 4. 3 only for the box itself and connected to the motherboard, 1 for the watercooling device which is also connected to the motherboard. Even with fancontrol: (base) avy@avy-Moi:~$ sudo pwmconfig
# pwmconfig revision 6243 (2014-03-20)
This program will search your sensors for pulse width modulation (pwm)
controls, and test each one to see if it controls a fan on
your motherboard. Note that many motherboards do not have pwm
circuitry installed, even if your sensor chip supports pwm.

We will attempt to briefly stop each fan using the pwm controls.
The program will attempt to restore each fan to full speed
after testing. However, it is ** very important ** that you
physically verify that the fans have been to full speed
after the program has completed.

Found the following devices:
hwmon0 is acpitz
hwmon1 is coretemp
hwmon2 is asus
hwmon3 is nouveau

Found the following PWM controls:
hwmon3/pwm1           current value: 0
hwmon3/pwm1 is currently setup for automatic speed control.
In general, automatic mode is preferred over manual mode, as
it is more efficient and it reacts faster. Are you sure that
you want to setup this output for manual control? (n) y

Giving the fans some time to reach full speed...
Found the following fan sensors:
hwmon2/fan1_input     current speed: 0 ... skipping!
hwmon3/fan1_input     current speed: 0 ... skipping!

There are no working fan sensors, all readings are 0.
Make sure you have a 3-wire fan connected.
You may also need to increase the fan divisors.


• I came across this problem a while back. From what I understand, the kernel is preventing lm-sensors from looking at fan usage, so I modified my GRUB settings to allow lm-sensors to access this information. First, open the configuration file:

sudo gedit /etc/default/grub


Then set the GRUB_CMDLINE_LINUX option to the following:

# This allows fan usage to be read by lm-sensors
GRUB_CMDLINE_LINUX="acpi_enforce_resources=lax"


Save the file and close, then update your GRUB settings:

sudo update-grub


Executing sensors in the terminal should show your fans' RPMs now. It may be the case that not every fan for your machine is being shown - for my machine, none of the ASST_FANs are shown.

Perhaps I could solve this issue by making a configuration for your mobo, as described here, but I am happy with the information I have been able to get with the adjustment to the GRUB configuration.