# Hotend Fan RPM Monitoring? **URL:** \ **Category:** General Discussion\ **Created:** [March 21, 2023, 9:16pm UTC](https://klipper.discourse.group/t/hotend-fan-rpm-monitoring/7379 "2023-03-21T21:16:17Z")\ **Posts on this page:** 1\ **Showing post:** 6
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [March 22, 2023, 3:58pm UTC](https://klipper.discourse.group/t/hotend-fan-rpm-monitoring/7379/6 "2023-03-22T15:58:33Z")
> [@gil80](#): > > If I use a 4-pin PWM fan, can I use the +/- on the fan header and the other two wires on the 2-pin Z-endstop? Nope. 4 wire fan is - Vcc - GND - PCM - Tacho Fan header is - Vcc - GND Z-Endstop is - Sig in - GND or Vcc depending on used logic --- _[View the full topic](https://klipper.discourse.group/t/hotend-fan-rpm-monitoring/7379)._