As John indicated, in your original picture I don’t believe the switch is wired normally closed. Step 1 is to repeat your experiment above with a shorted endstop and be absolutely sure the issue is the board and not something related to your wiring. You want to be careful when you short ‘s’ and ‘-’ since shorting ‘+’ to ground can damage a board. Take your current wiring out of the test by using some other wiring or method to connect the ‘-’ and the ‘s’ pins. Assuming directly shorting still indicates ‘Triggered,’ read on.
We have found on the forum that there are some SKR Pro boards that have issues with endstops. It is a hardware problem related to, in my opinion, a poor design probably combined with some out of spec components. If your board is one of the bad boards, you have the following choices:
- Get a replacement board
- Disconnect the endstop LEDs
- Add a pullup resistor between the ‘s’ pin and the ‘+’ pin for each endstop.
Disconnecting the LEDs does require you to modify your board. Pullup resistors can be added without physically modifying the SKR Pro. In the limited number of posts I’ve seen on the forum, both solutions worked in all cases.