Testing PA3

On the diagnosis page on the BLtouch I see there’s a way show if the switches are working. I’d like to see if I can test the PA3 pin, because I cannot get my BLtouch to Z-home. I have it down to either the BLtouch is faulty, or the pin on the mainboard is bad. Is there any way to check to see if my pin is bad on the mainboard?

In general, the pulse is too brief to be seen.

I have seen with non genuine BLTouch units, the color coding can be a bit off.
The wires connecting to the Z limit may be reversed.