Skr pro AlienFox relay

I purchased an AlienFox relay box and shorted my fan0 wiring it up. I put the ++ – from the pinout to my fan0 port and when I called M106, it would never M107 again. It’s stuck on now

I can move forward on my mistake, but how DO I wire this up??

FoxAlien Relay Module Relay Switch for CNC Router Machines, Routers and Dust Collector Connecting

I am going to just fire M42 on another pin and make it part of my post processor, but I am weiry now.

Much appreciated

Some questions to help guide you-

First can you post a picture of your SKR and how you wired it to the relay module?
Does your relay module work correctly if it is disconnected from the SKR?
On the SKR, if you measure Fan0 with a DMM, is it always on when the board is powered? (LIkely it is).

These FETs are low side switched and do not like driving a dead short, which is usually how they get blown. You note above that you shorted the fan0 wiring, so that’s nearly likely what happened.

I expect to see evidence in the picture you post of the FET having been overheated and likely smoked.

If the FoxAllen module isn’t working right, there are more affordable alternatives like those below (sadly, out of stock at the moment.)

Depending on what you’re driving with the relay module, even just a simple SSR would be better for many applications. (You don’t mention what you’re driving with it.)

You can work around this as you note by picking a different IO pin to drive your relay box. It’s important not to short the IO pins or FET outputs as that is a usual way to blow the IO.

Your Fan0 output could likely be repaired by replacing the FET.

I wired the positive and negative to the positive and negative from the skr to the AlienFox. It fired once and stayed on, so the relay is working correctly but now the fan0 won’t turn off

The positive on the skr is always on. It is wired straight to 12V.

Just the negative switches between ground and 12V. It is called “Low side drive”. If you’re not used to it, it can be a bit weird.

I don’t know anything about the relay you’re using. But I would try a simpler load (like a fan) before deciding the skr fan output was broken.

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