Brinkman Smoke N Grill vents?

I'm not familiar with your smoker. Hopefully someone will be along to assist. You may want to use the search bar. It can be your best friend.

I'm assuming your Smoke 'N Grill is a charcoal one, not electric (i.e. the ECB).  It sounds like you are asking about air into the charcoal pan.  I have the same smoker and didn't try to regulate air at the charcoal pan but in the lid.  By putting a damper in the lid, I can control my temperature around 200 - 300 pretty well.  I just took a Weber damper from an old one I had and adapted it onto the lid.  You can find them by searching on the web.