I hear the woosh though.
That's usually what I go by. I check the surface temps on the stove's rear burn chamber, and it usually confirms what the whooshing tells me: no whoosh means no AB, and temp in the 300-400 range; a steady, low whoosh means good AB function, and temp in the 500-800 range.
My biggest problem lately is the AB sometimes stalls out a while after I cut the air back to 1/4, so I may have ash buildup. I used to be able to close the primary air 100% and still get a long, steady secondary burn