Start out by man fancontrol to get a feel for what variables can be used in /etc/fancontrol. You will need the following when building the config: INTERVAL, FCTEMPS, FCFANS, MINTEMP, MAXTEMP, MINSTART, MINSTOP.
# Checks the temperature every 10 seconds.
# Maps a fan to a temp sensor, each separated by a space
# Maps a fan to the fan speed sensor
# The temperature below which the fan gets switched to minimum speed.
# The temperature over which the fan gets switched to maximum speed.
# Sets the minimum speed at which the fan begins spinning.
#The minimum speed at which the fan still spins.
I found a solution for my Vostro 5481. It might work for you (and others) as well.
git clone https://github.com/TomFreudenberg/dell-bios-fan-control.git
sudo ./dell-bios-fan-control 0
If you get an error like this
ioperm:: Operation not permitted
ioperm:: Operation not permitted 
4701 segmentation fault
you need to go to your BIOS/UEFI and disable SECURE BOOT. Then run the command again. Output should now be BIOS CONTROL DISABLED.
You can now go and check solutions for controlling the fan that suite your needs. If you want to quickly test, you can use i8kutils:
git clone https://github.com/vitorafsr/i8kutils
sudo ./i8kctl fan 2 2
Your fan should now run at the highest possible settings without the BIOS/UEFI interfering.
Controlling the fan in day to day business
Now that your BIOS/UEFI is no longer controlling the fan, you have to take care of it on your own. I'd suggest https://linux.die.net/man/8/fancontrol for this. It can easily be configured using pwmonfig (which ships with it) and adds itself as a system service.
Shoutout to Tom Freudenberg for creating dell-bios-fan-control and for pointing me to disabling SECURE_BOOT when I got the Operation not permitted error.