Obviously there is a red LED in the button so yeah, it will light up when something is enabled with that button.
Also the button illuminates red. Is this normal?
You should be able to get close to the right tuner setting just peaking up the noise on receive and then use the tuner thing. I have one for my 706 when I am mobile and it works the same.
I run the screwdriver antenna until the receiver noise peaks and go from there with the tuner thingie and usually find the sweet spot in a few seconds.
"Oh what a tangled web we weave when first we practice to receive."
-Otto Watt Sept. 5 1925