How to know the rangefinder is turning on and off with auxiliary switch

I am setting up a TF-Mini Plus and see that you can setup a auxiliary switch to turn it on and off. I have it setup facing down and get a good reading under the sonarrange. I have set rc7_option to range finder number 10 and under radio calibration in MP the radio 7 tab goes from 1100 to 1900.

How can I tell if the range finder is actually turning on and off?

Thank you,

Hello @DoubleD4485,
Where you able get any solutions to this ? I’m also in the same spot.