Got one to work... The part that tripped me up is that the gauge is expecting a numeric value for the state, so if you pass a string/text to it, it won't work. I started with this dataset
SELECT 1 AS QID, 'Yes' AS Answer
SELECT 2 AS Expr1, 'No' AS Expr2
SELECT 3 AS Expr1, 'Yes' AS Expr2
SELECT 4 AS Expr1, 'No' AS Expr2
SELECT 5 AS Expr1, 'Yes' AS Expr2
and it didn't work (no numeric value to connect to, because Expression2 is text.)
When I created a calculated value to convert Yes/No to 1/0, then it worked. I attached a super simple example. You could do the calculation for the indicator in your query/stored procedure instead of doing it in the report. I just did it that way to make it self-contained.
I removed the yellow light in my example, since it was mapping yes/no values to green/red.