# Fan shim random speed? **URL:** \ **Category:** Support\ **Created:** [February 20, 2020, 7:07pm UTC](https://forums.pimoroni.com/t/fan-shim-random-speed/13099 "2020-02-20T19:07:23Z")\ **Posts on this page:** 1\ **Showing post:** 8
**Author:** ![alphanumeric](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/alphanumeric/32/2729_2.png) [@alphanumeric](https://forums.pimoroni.com/u/alphanumeric)\ **Post date:** [February 20, 2020, 9:40pm UTC](https://forums.pimoroni.com/t/fan-shim-random-speed/13099/8 "2020-02-20T21:40:26Z")
Ok, disclaimer, I have a 10K pull down resistor wired from the fan control pin GPIO 18 to ground. I did this so my fan will shut off when I shut down my Pi. > [@How to turn Fan Shim Fan off on shutdown](https://forums.pimoroni.com/t/how-to-turn-fan-shim-fan-off-on-shutdown/12222): > > One minor annoyance for me is that the Fan on the Fan shim keeps running when I do a shutdown from Raspbian on my Pi 4B. This isn’t a complaint, more of an observation type deal. Why it does this is I believe a failsafe mode. If you install the Fan Shim and don’t install any software the fan will run and cool your Pi. Thats what you want to happen. You have to pull the fan control pin low to turn it off. Thats what the control Daemon does. When you do a shut down the Daemon stops running and t… That being said, with the service loaded as normal, a short quick button press does nothing. Which is likely why I thought the button didn’t do anything. A longer press gets me a blue flash from the LED and likely a switch to manual mode. Pressing the button after that makes my fan spin for a second or so and stop. My pull down resistor may be messing things up on me though? Repeated short presses just get me the same short spin and stop. Holding the button down gets me another blue flash and it appears it goes back into auto mode. It’s turning on off at what I had set the service too. --- _[View the full topic](https://forums.pimoroni.com/t/fan-shim-random-speed/13099)._