I had an M10N GPS attached to my Pixhawk6X.
The GPS was recognized correctly, but the GPS LED wouldn’t light up.
When I attached the GPS to another Pixhawk6C mini, the LED lit up without any problems.
The GPS wasn’t the issue, and I couldn’t figure out the reason for the problem for a while.
Then I solved it from a different reason.
I had a PM02v3 power module attached to the Pixhawk6X,
but since it’s an analog type, it couldn’t be used with the Pixhawk6X.
I realized that only the digital PD02 would work, so I swapped it out.
After that, the LED started working.
It seems that when you try to use an analog PM with the 6X, the I2C settings get messed up.