Thank you for the tipp. Now it is working. Here my configuration, maybe it is helpful to others:
My config (nano /etc/thinkfan.conf):
hwmon /sys/devices/platform/thinkpad_hwmon/hwmon/hwmon4/temp1_input
( you can find the information with this command: find /sys/devices -type f -name "temp*input")
(0, 0, 58)
(1, 55, 63)
(2, 61, 73)
(3, 70, 78)
(4, 76, 88)
(5, 85, 93)
(7, 90, 32767)
(it works with my Thinkpad T430s with NVIDIA)
and created this file (/etc/modprobe.d/thinkpad_acpi.conf):
options thinkpad_acpi fan_control=1
I also used following commands:
sensors-detect
modprobe thinkpad_acpi
systemctl enable thinkfan
reboot