echo 255 > /sys/kernel/debug/tegra_fan/target_pwm   (L4T Old version)

Or

echo 255 >/sys/devices/pwm-fan/target_pwm

Or

echo  255 > /sys/devices/platform/pwm-fan/hwmon/hwmon1/device/hwmon/hwmon1/pwm1   (Jetpack5.*)

Run command：

head -n 1 /etc/nv_tegra_release