The Chachamim were Gozer things even without a connection to any Issur. For example, the Sandel Hamesumar. As leaders and policy setters we must listen to them. It is a form of Psak when they declare something important for the well-being of Yiddishkeit.
This is entirely separate from asking personal advice, in which case it is advisable to follow advice of a Torah-trained mind but you don’t have to.
You must listen to your Rebbe when he commands you to do something.
To listen to someone who has Ruach Hakodesh is more than just advisable and disobeying him might bump with some Issurim. Ruach Hakodesh might be on the level of Siyata Dishmaya, where it is a decision with a guided bias. I know of numerous instances of such advice from Gedolim that sounds prophetic.